Immunologically significant herpes simplex virus antigens and methods for identifying and using same

ABSTRACT

The invention provides HSV antigens that are useful for the prevention and treatment of HSV infection. Disclosed herein are epitopes confirmed to be recognized by T-cells derived from herpetic lesions. T-cells having specificity for antigens of the invention have demonstrated cytotoxic activity against cells loaded with virally-encoded peptide epitopes, and in many cases, against cells infected with HSV. The identification of immunogenic antigens responsible for T-cell specificity provides improved anti-viral therapeutic and prophylactic strategies. Compositions containing antigens or polynucleotides encoding antigens of the invention provide effectively targeted vaccines for prevention and treatment of HSV infection.

This application is a divisional of application Ser. No. 09/672,595,filed Sep. 28, 2000, now U.S. Pat. No. 6,413,518, which applicationclaims benefit of U.S. provisional patent applications No. 60/157,181,filed Sep. 30, 1999, No. 60/203,660, filed May 12, 2000, and No.60/218,104, filed Jul. 13, 2000, the entire contents of each of whichare incorporated herein by reference. Throughout this applicationvarious publications are referenced. The disclosures of thesepublications in their entireties are hereby incorporated by referenceinto this application in order to describe more fully the state of theart to which this invention pertains.

The invention disclosed herein was made with government support underGrant Nos. AI34616, AI30731 and CA70017, awarded by the NationalInstitutes of Health. The government has certain rights in thisinvention.

TECHNICAL FIELD OF THE INVENTION

The invention relates to molecules, compositions and methods that can beused for the treatment and prevention of HSV infection. Moreparticularly, the invention identifies epitopes of HSV proteins that canbe used for the development of methods, molecules and compositionshaving the antigenic specificity of HSV-specific T cells, and inparticular, of CD8+ T cells.

BACKGROUND OF THE INVENTION

Cellular immune responses are required to limit the severity ofrecurrent HSV infection in humans. Initial genital HSV-2 infections areprolonged and severe, while recurrences are less severe and morefrequently asymptomatic. Resolution of primary HSV-2 infection isassociated with infiltration of antigen-specific T cells, including CD8+cytotoxic T lymphocytes (CTLs). Serial lesion biopsy studies ofrecurrent HSV-2 infection in humans has shown a shift to CD8+predominance as lesions mature and correlation of local CTL activitywith virus clearance (Koelle, D M et al., J. Clin. Invest. 1998,101:1500-1508; Cunningham, A L et al., J. Clin. Invest. 1985,75:226-233). Thus, HSV antigens recognized by CD8+ CTL can be used fornovel therapies and vaccines.

The complete DNA sequence of herpes simplex virus (HSV) is approximately150 kb and encodes about 85 known genes, each of which encodes a proteinin the range of 50-1000 amino acids in length. Unknown are theimmunogenic epitopes within these proteins, each epitope approximately9-12 amino acids in length, that are capable of eliciting an effective Tcell immune response to viral infection.

There remains a need to identify specific epitopes capable of elicitingan effective immune response to HSV infection. Such information can leadto the identification of more effective immunogenic antigens useful forthe prevention and treatment of HSV infection.

SUMMARY OF THE INVENTION

The invention provides HSV antigens, polypeptides comprising HSVantigens, polynucleotides encoding the polypeptides, vectors, andrecombinant viruses containing the polynucleotides, antigen-presentingcells (APCs) presenting the polypeptides, immune cells directed againstHSV, and pharmaceutical compositions. The pharmaceutical compositionscan be used both prophylactically and therapeutically. The antigens ofthe invention are recognized by T cells recovered from herpetic lesions.The invention additionally provides methods, including methods forpreventing and treating HSV infection, for killing HSV-infected cells,for inhibiting viral replication, for enhancing secretion of antiviraland/or immunomodulatory lymphokines, and for enhancing production ofHSV-specific antibody. For preventing and treating HSV infection, forenhancing secretion of antiviral and/or immunomodulatory lymphokines,for enhancing production of HSV-specific antibody, and generally forstimulating and/or augmenting HSV-specific immunity, the methodcomprises administering to a subject a polypeptide, polynucleotide,recombinant virus, APC, immune cell or composition of the invention. Themethods for killing HSV-infected cells and for inhibiting viralreplication comprise contacting an HSV-infected cell with an immune cellof the invention. The immune cell of the invention is one that has beenstimulated by an antigen of the invention or by an APC that presents anantigen of the invention. A method for producing such immune cells isalso provided by the invention. The method comprises contacting animmune cell with an APC, preferably a dendritic cell, that has beenmodified to present an antigen of the invention. In a preferredembodiment, the immune cell is a T cell such as a CD4+ or CD8+ T cell.

In one embodiment, the invention provides a composition comprising anHSV polypeptide. The polypeptide comprises an ICP0 or U_(L)47 protein ora fragment thereof. In one embodiment, the fragment comprises aminoacids 92-101 of ICP0 or a substitutional variant thereof. In otherembodiments, the fragment comprises amino acids 289-298, 548-557,550-559, 551-559 and/or 551-561 of U_(L)47 or a substitutional variantthereof. Also provided is an isolated polynucleotide that encodes apolypeptide of the invention, and a composition comprising thepolynucleotide. The invention additionally provides a recombinant virusgenetically modified to express a polynucleotide of the invention, and acomposition comprising the recombinant virus. In preferred embodiments,the virus is a vaccinia virus, canary pox virus, HSV, lentivirus,retrovirus or adenovirus. A composition of the invention can be apharmaceutical composition. The composition can optionally comprise apharmaceutically acceptable carrier and/or an adjuvant.

The invention additionally provides a method of identifying animmunogenic epitope of an infectious organism, such as a virus,bacterium or parasite. Preferably, the infectious organism is a virus,such as HSV. In one embodiment, the method comprises preparing acollection of random fragments of the organismal genome. The fragmentscan be prepared using any of a variety of standard methods, including,but not limited to, digestion with restriction enzymes and mechanicalfragmentation, such as by controlled sonication (Mougneau E et al.,Science 1995, 268:563-66). In a preferred embodiment, the organism isHSV-2 and the fragments of viral genome are prepared by digestion withSau3A I. Examples of other restriction enzymes that can be used include,but are not limited to, Apa I, Sma I, and Alu I. The fragments ofgenomic DNA are then ligated into a vector, preferably by using apartial fill-in reaction. A preferred vector is a member of the pcDNA3.1(+) his series. The fragments are then expressed using conventionaltechniques. Preferably, the expression is performed using a Cos-7transfection method (De Plaen E et al. In: Lefkowits I, ed. ImmunologyMethods Manual, v. 2. New York: Academic Press, 1997:691-718). The Cos-7cells can be co-transfected with an appropriate HLA molecule capable ofpresenting the target antigen.

The ability of the expressed polypeptide to elicit a cellular immuneresponse is then assayed. Ability to elicit a cellular immune responseis indicative of the presence of an immunogenic epitope. Assays that canbe used to detect ability to elicit a cellular immune response include,but are not limited to, cytotoxicity assays and lymphokine secretionassays. In one embodiment, the assay is an interferon-gamma assay.

In a preferred embodiment, the invention provides a method foridentifying HSV epitopes immunogenic for CD8+ T cells. The methodcomprises obtaining CD8+ T cells from an HSV lesion, and assaying theobtained T cells to identify T cells having ability to recognizeHSV-infected cells. The method further comprises obtaining andfragmenting a nucleic acid preparation from HSV, expressing one or morefragments of the obtained nucleic acid, and assaying the expressedfragments for antigenic reactivity with the identified HSV-specific Tcells. An expressed fragment having reactivity with the HSV-specific Tcells is identified as encoding an HSV epitope immunogenic for CD8+ Tcells.

The above steps can be repeated with subfragments of the genomefragments. The method can further comprise sequencing a fragment of thegenome. In one embodiment, the assaying of T cells comprises performinga cytotoxicity assay or an interferon-gamma assay. The assaying can beperformed with an immune cell derived from a subject that has beenexposed to the infectious organism. In preferred embodiments, the cellis derived from a site of active infection, such as skin or cervix, orfrom blood of an infected subject.

The invention further provides immunogenic epitopes identified by themethod of the invention, polypeptides comprising the epitopes, andpolynucleotides encoding the polypeptides. Suitable infectious organismsinclude bacteria, parasites and viruses. Examples of viruses include DNAand RNA viruses, both double-stranded and single-stranded. The method ofthe invention provides a strategy for combating a variety of infectiousorganisms, including those that exhibit significant variability, asknowledge of the organism's nucleic acid sequence is not required.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1A shows fluorescence detection of TCR Cβ-Vβ PCR products (12 of 24Vβ families shown) in bulk CD8-enriched PBMC from subject RW. Two Vβprimers (indicated) were used per panel in duplex analysis. X axis:molecular weights of PCR products shown at TOP based on fluorescentmarkers. Y axis: relative fluorescence intensity.

FIG. 1B shows fluorescence detection of TCR Cβ-Vβ PCR products (12 of 24Vβ families shown) in bulk CD8-enriched lesion-infiltrating lymphocytes(LIL) from primary HSV-2 biopsy. Two Vβ primers (indicated) were usedper panel in duplex analysis. X axis: molecular weights of PCR productsshown at TOP based on fluorescent markers. Y axis: relative fluorescenceintensity.

FIG. 2A shows proliferative responses of bulk-expanded cervicalcytobrush-derived lymphocytes.

FIG. 2B shows cytotoxic responses of bulk-expanded cervicalcytobrush-derived lymphocytes, plotted as percent specific release.

FIG. 3 is a schematic representation of the positive genomic cloneisolated from Sau3A I library of HSV-2 DNA (second line), whichcontained part of the ICP0 gene. The genomic clone was transfected intocells and primer A used for cDNA synthesis. The exon-1/exon2 C-A (fifthline) and HLA B45 cDNAs stimulated interferon-gamma secretion from Tcell clone (TCC) RW51 after transfection into Cos-7 cells. Exon-1 B-CcDNA (fourth line) was negative.

FIG. 4 is a bar graph showing CTL activity of RW51 against vaccinia ICP0and indicated concentrations of synthetic ICP0 92-105. Four-hour ⁵¹Crrelease assay with effector:target ratio 10:1. Spontaneous release all<20%.

FIG. 5 is a graph showing CTL activity of RW51 against indicatedconcentrations of synthetic ICP0 92-101. Four-hour ⁵¹Cr release assaywith effector:target ratio 10:1. Spontaneous release all <20%.

FIG. 6 is a graph showing CTL activity of lymphocytes subject RW,derived from peripheral blood and stimulated with a peptide of HSV-2ICP0 amino acids 92-101. Four-hour ⁵¹Cr release assay witheffector:target ratio of 10:1. Spontaneous release <20%. For each pairof bars, the upper bar represents data from a lesion-derived CD8 cloneand the lower bar represents data from PBMC stimulated with peptide.

FIG. 7 shows confirmation of HLA restricting allele, HSV-2 reactivity,and IFN-gamma secretion by lesion CD8 clones.

FIG. 8A shows peptide dose-response for lesion CD8 clone dkRW.1991.22worked up by expression cloning.

FIG. 8B shows peptide dose-response for lesion CD8 clone RW.1997.51worked up by expression cloning.

FIG. 8C shows peptide dose-response for lesion CD8 clone HV.1999.23worked up by expression cloning.

FIG. 9 shows that A*0201 restricted, U_(L)47 289-298-specific CD8 CTLcross-react with B*4402 or B*4403.

FIGS. 10A-O show the presence of U_(L)47-specific CTL in peripheralblood lymphocytes.

FIG. 10A shows specific release for subject 1874 elicited by U_(L)47289-298.

FIG. 10B shows specific release for subject 1874 elicited by U_(L)47551-559.

FIG. 10C shows specific release for subject 1874 elicited by gB2443-451.

FIG. 10D shows specific release for subject 7282 elicited by U_(L)47289-298.

FIG. 10E shows specific release for subject 7282 elicited by U_(L)47551-559.

FIG. 10F shows specific release for subject 7282 elicited by gB2443-451.

FIG. 10G shows specific release for subject 9107 elicited by U_(L)47289-298.

FIG. 10H shows specific release for subject 9107 elicited by U_(L)47551-559.

FIG. 10I shows specific release for subject 9107 elicited by gB2443-451.

FIG. 10J shows specific release for subject 9383 elicited by U_(L)47289-298.

FIG. 10K shows specific release for subject 9383 elicited by U_(L)47551-559.

FIG. 10L shows specific release for subject 9383 elicited by gB2443-451.

FIG. 10M shows specific release for subject 9410 elicited by U_(L)47289-298.

FIG. 10N shows specific release for subject 9410 elicited by U_(L)47551-559.

FIG. 10O shows specific release for subject 9410 elicited by gB2443-451.

FIG. 11A is a graph showing results of an IFN-gamma ELISPOT assay, inELISPOTS per well, as a function of peptide concentration (μg/ml).Results are shown for 5 9-mer U_(L)47 peptides tested: 548-556 (solidcircles); 549-557 (open circles); 550-558 (solid triangles); 551-559(open triangles); 552-560 (squares).

FIG. 11B is a graph showing results of an IFN-gamma ELISPOT assay, inELISPOTS per well, as a function of peptide concentration (μg/ml).Results are shown for 5 10-mer U_(L)47 peptides tested: 548-557 (solidcircles); 549-558 (open circles); 550-559 (solid triangles); 551-560(open triangles); 552-561 (squares).

FIG. 12 is a bar graph showing results of an IFN-gamma ELISPOT assay, inELISPOTS per well, for each of various HPLC fractions of peptides elutedfrom HLA-A2 on C1R-A2/3D9.6H7 cells. The results show that fractions 17,18 and 23 contain peptides that are recognized by CTL clone cpRW22. Theinset shows data for various controls, including T cells alone,C1R-A2/3D9.5A1, C1R-A2/3D9.6H7, C1R-A2/HSV-2, C1R-A2/HSV-1, and C1R-A2.

FIG. 13A is a bar graph showing results of an IFN-gamma ELISPOT assay,in ELISPOTS per well, for each of various HPLC subfractions of fraction17. The results show that subfractions of fraction 17 contain peptidesfrom C1RA2/3D9.6H7 that are recognized by CTL clone cpRW22. Arrowsindicate peptides corresponding to SEQ ID NO: 3, 1 and 2, respectively.

FIG. 13B is a bar graph showing results of an IFN-gamma ELISPOT assay,in ELISPOTS per well, for each of various HPLC subfractions of fraction18. The results show that subfractions of fraction 18 contain peptidesfrom C1R-A2/3D9.6H7 that are recognized by CTL clone cpRW22. Arrowsindicate peptides corresponding to SEQ ID NO: 3, 1 and 2, respectively.

FIG. 13C is a bar graph showing results of an IFN-gamma ELISPOT assay,in ELISPOTS per well, for each of various controls: clone 22 only;C1R-A2/3D9.5A1; C1R-A2/3D9.6H7; and T2 cells.

FIG. 14 is a bar graph showing results of an IFN-gamma ELISPOT assay, inELISPOTS per well, for each of various HPLC subfractions of fraction 23from C1R-A2/3D9.6H7 cells. The results show that subfraction 37sensitizes T2 cells for recognition by CTL clone cpRW22. The activity inthis fraction has the same mobility on HPLC as U_(L)47/550-559. Arrowsindicate peptides corresponding to SEQ ID NO: 3, 1 and 2, respectively.The inset shows data for controls, including T cells alone andC1R-A2/3D9.6H7.

FIG. 15A shows the results of HPLC fractionation of HSV2 syntheticpeptide LGLADTVVAC (SEQ ID NO: 1; U_(L)47/550-559). The peptide was runthrough HPLC under the subfractionation conditions and found to elute infraction 37.

FIG. 15B shows the results of HPLC fractionation of HSV2 syntheticpeptide GLADTVVACV (SEQ ID NO: 2; U_(L)47/551-560). The peptide was runthrough HPLC under the subfractionation conditions and found to elute infraction 40/41.

FIG. 15C shows the results of HPLC fractionation of HSV2 syntheticpeptide GLADTVVAC (SEQ ID NO: 3; U_(L)47/551-559). The peptide was runthrough HPLC under the subfractionation conditions and found to elute infraction 32.

FIG. 16 shows mass spectra data, plotted as relative abundance as afunction of m/z, for fraction 23/subfraction 37 from C1R-A2/3D9.6H7.These data show that a peptide with the same mass (MW=961) asU_(L)47/550-559 is present in this subfraction.

FIG. 17 shows the sequences (SEQ ID NO: 14-17) of various primers usedfor PCR to demonstrate that the C1R-A2/3D9.6H7 cells contain at leasttwo retroviral inserts derived from HSV-2.

FIG. 18A shows the results of the PCR analysis of retroviral insertsfrom C1R-A2/3D9.6H7 cells, confirming that these cells contain insertsfrom HSV-2. Bands 2, 4 and 8 refer to the portions of the U_(L)47 insertillustrated in FIG. 18B; band 7 refers to the U_(L)52 insert illustratedin FIG. 18C.

FIG. 18B is a schematic illustration of the large portion of the U_(L)47gene encoded by a retroviral insert from C1R-A2/3D9.6H7 cells. Thisinsert includes a portion encoding the U_(L)47/550-559 peptide (SEQ IDNO: 1).

FIG. 18C is a schematic illustration of the two fragments of the U_(L)52gene encoded by a second retroviral insert from C1R-A2/3D9.6H7 cells.

FIG. 19 is a bar graph showing that U_(L)47 gene-transfected VA13/A2cells are recognized by CD8+ T cell clone cpRW22, as determined byinterferon-gamma secretion measured in ELISPOTS/well. Targets were VA13fibroblasts stably expressing HLA-A2. Targets were pulsed with U_(L)47peptide or transiently transfected with U_(L)47 expression plasmidclones #2, #4 or #6. Responders were the cpRW22 CD8+ T cell clone.

FIGS. 20A-L are graphs showing CTL responses by different HLA-A2 donors,plotted as percent specific lysis as a function of effector:targetratio. Targets were pulsed with either no peptide (solid circles), thestimulating peptide (open circles), or a control peptide derived fromHIV (triangles).

FIG. 20A shows results for donor RW1874. PBMC were stimulated withinfluenza M1/58-66.

FIG. 20B shows results for donor RW1874. PBMC were stimulated withU_(L)47/550-559.

FIG. 20C shows results for donor RW1874. PBMC were stimulated withU_(L)47/289-298.

FIG. 20D shows results for donor HV5101. PBMC were stimulated withM1/58-66.

FIG. 20E shows results for donor HV5101. PBMC were stimulated withU_(L)47/550-559.

FIG. 20F shows results for donor HV5101. PBMC were stimulated withU_(L)47/289-298.

FIG. 20G shows results for donor AD120. PBMC were stimulated withM1/58-66.

FIG. 20H shows results for donor AD120. PBMC were stimulated withU_(L)47/550-559.

FIG. 20I shows results for donor AD120. PBMC were stimulated withU_(L)47/289-298.

FIG. 20J shows results for donor AD124. PBMC were stimulated withM1/58-66.

FIG. 20K shows results for donor AD124. PBMC were stimulated withU_(L)47/550-559.

FIG. 20L shows results for donor AD124. PBMC were stimulated withU_(L)47/289-298.

DETAILED DESCRIPTION OF THE INVENTION

The invention provides HSV antigens that are useful for the preventionand treatment of HSV infection. Disclosed herein are antigens and/ortheir constituent epitopes confirmed to be recognized by T-cells derivedfrom herpetic lesions. In some embodiments, T-cells having specificityfor antigens of the invention have demonstrated cytotoxic activityagainst virally infected cells. The identification of immunogenicantigens responsible for T-cell specificity facilitates the developmentof improved anti-viral therapeutic and prophylactic strategies.Compositions containing antigens or polynucleotides encoding antigens ofthe invention provide effectively targeted vaccines for prevention andtreatment of HSV infection.

Definitions

All scientific and technical terms used in this application havemeanings commonly used in the art unless otherwise specified. As used inthis application, the following words or phrases have the meaningsspecified.

As used herein, “polypeptide” includes proteins, fragments of proteins,and peptides, whether isolated from natural sources, produced byrecombinant techniques or chemically synthesized. Polypeptides of theinvention typically comprise at least about 6 amino acids.

As used herein, “HSV polypeptide” includes HSV-1 and HSV-2, unlessotherwise indicated. References to amino acids of HSV proteins orpolypeptides are based on the genomic sequence information regardingHSV-2 as described in A. Dolan et al., 1998, J. Virol. 72(3):2010-2021.As noted below, the predicted polypeptide sequence of ICP0 of HSV-2based on sequencing RNA from cells transfected with a fragment of ICP0differs from the published sequence by the omission of amino acid Q26.

As used herein, “substitutional variant” refers to a molecule having oneor more amino acid substitutions or deletions in the indicated aminoacid sequence, yet retaining the ability to be specifically recognizedby an immune cell. The amino acid sequence of a substitutional variantis preferably at least 80% identical to the native amino acid sequence,or more preferably, at least 90% identical to the native amino acidsequence. One method for determining whether a molecule can bespecifically recognized by an immune cell is the cytotoxicity assaydescribed in D. M. Koelle et al., 1997, Human Immunol. 53:195-205. Othermethods for determining whether a molecule can be specificallyrecognized by an immune cell are described in the examples providedhereinbelow, including the ability to stimulate secretion ofinterferon-gamma or the ability to lyse cells presenting the molecule.An immune cell will specifically recognize a molecule when, for example,stimulation with the molecule results in secretion of greaterinterferon-gamma than stimulation with control molecules. For example,the molecule may stimulate greater than 5 pg/ml, or preferably greaterthan 10 pg/ml, interferon-gamma secretion, whereas a control moleculewill stimulate less than 5 pg/ml interferon-gamma.

As used herein, “vector” means a construct, which is capable ofdelivering, and preferably expressing, one or more gene(s) orsequence(s) of interest in a host cell. Examples of vectors include, butare not limited to, viral vectors, naked DNA or RNA expression vectors,plasmid, cosmid or phage vectors, DNA or RNA expression vectorsassociated with cationic condensing agents, DNA or RNA expressionvectors encapsulated in liposomes, and certain eukaryotic cells, such asproducer cells.

As used herein, “expression control sequence” means a nucleic acidsequence that directs transcription of a nucleic acid. An expressioncontrol sequence can be a promoter, such as a constitutive or aninducible promoter, or an enhancer. The expression control sequence isoperably linked to the nucleic acid sequence to be transcribed.

The term “nucleic acid” or “polynucleotide” refers to adeoxyribonucleotide or ribonucleotide polymer in either single- ordouble-stranded form, and unless otherwise limited, encompasses knownanalogs of natural nucleotides that hybridize to nucleic acids in amanner similar to naturally occurring nucleotides.

As used herein, “antigen-presenting cell” or “APC” means a cell capableof handling and presenting antigen to a lymphocyte. Examples of APCsinclude, but are not limited to, macrophages, Langerhans-dendriticcells, follicular dendritic cells, B cells, monocytes, fibroblasts andfibrocytes. Dendritic cells are a preferred type of antigen presentingcell. Dendritic cells are found in many non-lymphoid tissues but canmigrate via the afferent lymph or the blood stream to the T-dependentareas of lymphoid organs. In non-lymphoid organs, dendritic cellsinclude Langerhans cells and interstitial dendritic cells. In the lymphand blood, they include afferent lymph veiled cells and blood dendriticcells, respectively. In lymphoid organs, they include lymphoid dendriticcells and interdigitating cells.

As used herein, “modified” to present an epitope refers toantigen-presenting cells (APCs) that have been manipulated to present anepitope by natural or recombinant methods. For example, the APCs can bemodified by exposure to the isolated antigen, alone or as part of amixture, peptide loading, or by genetically modifying the APC to expressa polypeptide that includes one or more epitopes.

As used herein, “pharmaceutically acceptable salt” refers to a salt thatretains the desired biological activity of the parent compound and doesnot impart any undesired toxicological effects. Examples of such saltsinclude, but are not limited to, (a) acid addition salts formed withinorganic acids, for example hydrochloric acid, hydrobromic acid,sulfuric acid, phosphoric acid, nitric acid and the like; and saltsformed with organic acids such as, for example, acetic acid, oxalicacid, tartaric acid, succinic acid, maleic acid, fumaric acid, gluconicacid, citric acid, malic acid, ascorbic acid, benzoic acid, tannic acid,pamoic acid, alginic acid, polyglutamic acid, naphthalenesulfonic acids,naphthalenedisulfonic acids, polygalacturonic acid; (b) salts withpolyvalent metal cations such as zinc, calcium, bismuth, barium,magnesium, aluminum, copper, cobalt, nickel, cadmium, and the like; or(c) salts formed with an organic cation formed fromN,N′-dibenzylethylenediamine or ethylenediamine; or (d) combinations of(a) and (b) or (c), e.g., a zinc tannate salt; and the like. Thepreferred acid addition salts are the trifluoroacetate salt and theacetate salt.

As used herein, “pharmaceutically acceptable carrier” includes anymaterial which, when combined with an active ingredient, allows theingredient to retain biological activity and is non-reactive with thesubject's immune system. Examples include, but are not limited to, anyof the standard pharmaceutical carriers such as a phosphate bufferedsaline solution, water, emulsions such as oil/water emulsion, andvarious types of wetting agents. Preferred diluents for aerosol orparenteral administration are phosphate buffered saline or normal (0.9%)saline.

Compositions comprising such carriers are formulated by well knownconventional methods (see, for example, Remington's PharmaceuticalSciences, Chapter 43, 14th Ed., Mack Publishing Co, Easton Pa. 18042,USA).

As used herein, “adjuvant” includes those adjuvants commonly used in theart to facilitate the stimulation of an immune response. Examples ofadjuvants include, but are not limited to, helper peptide; aluminumsalts such as aluminum hydroxide gel (alum) or aluminum phosphate;Freund's Incomplete Adjuvant and Complete Adjuvant (Difco Laboratories,Detroit, Mich.); Merck Adjuvant 65 (Merck and Company, Inc., Rahway,N.J.); AS-2 (Smith-Kline Beecham); QS-21 (Aquilla); MPL or 3d-MPL(Corixa Corporation, Hamilton, Mont.); LEIF; salts of calcium, iron orzinc; an insoluble suspension of acylated tyrosine; acylated sugars;cationically or anionically derivatized polysaccharides;polyphosphazenes; biodegradable microspheres; monophosphoryl lipid A andquil A; muramyl tripeptide phosphatidyl ethanolamine or animmunostimulating complex, including cytokines (e.g., GM-CSF orinterleukin-2, -7 or -12) and immunostimulatory DNA sequences. In someembodiments, such as with the use of a polynucleotide vaccine, anadjuvant such as a helper peptide or cytokine can be provided via apolynucleotide encoding the adjuvant.

As used herein, “a” or “an” means at least one, unless clearly indicatedotherwise.

HSV Polypeptides

In one embodiment, the invention provides an isolated herpes simplexvirus (HSV) polypeptide, wherein the polypeptide comprises an ICP0 orU_(L)47 protein or a fragment thereof. In one embodiment, the fragmentcomprises amino acids 92-101 of ICP0 or a substitutional variantthereof. In another embodiment, the fragment comprises amino acids289-298, 548-557, 550-559, 551-559 and/or 551-561 of U_(L)47 or asubstitutional variant thereof. The reference to amino acid residues ismade with respect to the proteins of the HSV-2 genome as described in A.Dolan et al., 1998, J. Virol. 72(3):2010-2021.

The polypeptide can be a fusion protein. In one embodiment, the fusionprotein is soluble. A soluble fusion protein of the invention can besuitable for injection into a subject and for eliciting an immuneresponse. Within certain embodiments, a polypeptide can be a fusionprotein that comprises multiple polypeptides as described herein, orthat comprises at least one polypeptide as described herein and anunrelated sequence. A fusion partner may, for example, assist inproviding T helper epitopes (an immunological fusion partner),preferably T helper epitopes recognized by humans, or may assist inexpressing the protein (an expression enhancer) at higher yields thanthe native recombinant protein. Certain preferred fusion partners areboth immunological and expression enhancing fusion partners. Otherfusion partners may be selected so as to increase the solubility of theprotein or to enable the protein to be targeted to desired intracellularcompartments. Still further fusion partners include affinity tags, whichfacilitate purification of the protein.

Fusion proteins may generally be prepared using standard techniques,including chemical conjugation. Preferably, a fusion protein isexpressed as a recombinant protein, allowing the production of increasedlevels, relative to a non-fused protein, in an expression system.Briefly, DNA sequences encoding the polypeptide components may beassembled separately, and ligated into an appropriate expression vector.The 3′ end of the DNA sequence encoding one polypeptide component isligated, with or without a peptide linker, to the 5′ end of a DNAsequence encoding the second polypeptide component so that the readingframes of the sequences are in phase. This permits translation into asingle fusion protein that retains the biological activity of bothcomponent polypeptides.

A peptide linker sequence may be employed to separate the first and thesecond polypeptide components by a distance sufficient to ensure thateach polypeptide folds into its secondary and tertiary structures. Sucha peptide linker sequence is incorporated into the fusion protein usingstandard techniques well known in the art. Suitable peptide linkersequences may be chosen based on the following factors: (1) theirability to adopt a flexible extended conformation; (2) their inabilityto adopt a secondary structure that could interact with functionalepitopes on the first and second polypeptides; and (3) the lack ofhydrophobic or charged residues that might react with the polypeptidefunctional epitopes. Preferred peptide linker sequences contain Gly, Asnand Ser residues. Other near neutral amino acids, such as Thr and Alamay also be used in the linker sequence. Amino acid sequences which maybe usefully employed as linkers include those disclosed in Maratea etal., 1985, Gene 40:39-46; Murphy et al., 1986, Proc. Nad. Acad. Sci. USA83:8258-8262; U.S. Pat. No. 4,935,233 and U.S. Pat. No. 4,751,180. Thelinker sequence may generally be from 1 to about 50 amino acids inlength. Linker sequences are not required when the first and secondpolypeptides have non-essential N-terminal amino acid regions that canbe used to separate the functional domains and prevent stericinterference.

The ligated DNA sequences are operably linked to suitabletranscriptional or translational regulatory elements. The regulatoryelements responsible for expression of DNA are located 5′ to the DNAsequence encoding the first polypeptides. Similarly, stop codonsrequired to end translation and transcription termination signals arepresent 3′ to the DNA sequence encoding the second polypeptide.

Fusion proteins are also provided that comprise a polypeptide of thepresent invention together with an unrelated immunogenic protein.Preferably the immunogenic protein is capable of eliciting a recallresponse. Examples of such proteins include tetanus, tuberculosis andhepatitis proteins (see, for example, Stoute et al., 1997, New Engl. J.Med., 336:86-9).

Within preferred embodiments, an immunological fusion partner is derivedfrom protein D, a surface protein of the gram-negative bacteriumHaemophilus influenza B (WO 91/18926). Preferably, a protein Dderivative comprises approximately the first third of the protein (e.g.,the first N-terminal 100-110 amino acids), and a protein D derivativemay be lipidated. Within certain preferred embodiments, the first 109residues of a Lipoprotein D fusion partner is included on the N-terminusto provide the polypeptide with additional exogenous T-cell epitopes andto increase the expression level in E. coli (thus functioning as anexpression enhancer). The lipid tail ensures optimal presentation of theantigen to antigen presenting cells. Other fusion partners include thenon-structural protein from influenza virus, NS1 (hemaglutin).Typically, the N-terminal 81 amino acids are used, although differentfragments that include T-helper epitopes may be used.

In another embodiment, the immunological fusion partner is the proteinknown as LYTA, or a portion thereof (preferably a C-terminal portion).LYTA is derived from Streptococcus pneumoniae, which synthesizes anN-acetyl-L-alanine amidase known as amidase LYTA (encoded by the LytAgene; Gene 43:265-292, 1986). LYTA is an autolysin that specificallydegrades certain bonds in the peptidoglycan backbone. The C-terminaldomain of the LYTA protein is responsible for the affinity to thecholine or to some choline analogues such as DEAE. This property hasbeen exploited for the development of E. coli C-LYTA expressing plasmidsuseful for expression of fusion proteins. Purification of hybridproteins containing the C-LYTA fragment at the amino terminus has beendescribed (see Biotechnology 10:795-798, 1992). Within a preferredembodiment, a repeat portion of LYTA may be incorporated into a fusionprotein. A repeat portion is found in the C-terminal region starting atresidue 178. A particularly preferred repeat portion incorporatesresidues 188-305.

In some embodiments, it may be desirable to couple a therapeutic agentand a polypeptide of the invention, or to couple more than onepolypeptide of the invention. For example, more than one agent orpolypeptide may be coupled directly to a first polypeptide of theinvention, or linkers that provide multiple sites for attachment can beused. Alternatively, a carrier can be used. Some molecules areparticularly suitable for intercellular trafficking and proteindelivery, including, but not limited to, VP22 (Elliott and O'Hare, 1997,Cell 88:223-233; see also Kim et al., 1997, J. Immunol. 159:1666-1668;Rojas et al., 1998, Nature Biotechnology 16:370; Kato et al., 1998, FEBSLett. 427(2):203-208; Vives et al., 1997, J. Biol. Chem.272(25):16010-7; Nagahara et al., 1998, Nature Med. 4(12):1449-1452).

A carrier may beat the agents or polypeptides in a variety of ways,including covalent bonding either directly or via a linker group.Suitable carriers include proteins such as albumins (e.g., U.S. Pat. No.4,507,234, to Kato et al.), peptides and polysaccharides such asaminodextran (e.g., U.S. Pat. No. 4,699,784, to Shih et al.). A carriermay also beat an agent by noncovalent bonding or by encapsulation, suchas within a liposome vesicle (e.g., U.S. Pat. Nos. 4,429,008 and4,873,088).

In general, polypeptides (including fusion proteins) and polynucleotidesas described herein are isolated. An “isolated” polypeptide orpolynucleotide is one that is removed from its original environment. Forexample, a naturally occurring protein is isolated if it is separatedfrom some or all of the coexisting materials in the natural system.Preferably, such polypeptides are at least about 90% pure, morepreferably at least about 95% pure and most preferably at least about99% pure. A polynucleotide is considered to be isolated if, for example,it is cloned into a vector that is not part of the natural environment.

The polypeptide can be isolated from its naturally occurring form,produced by recombinant means or synthesized chemically. Recombinantpolypeptides encoded by DNA sequences described herein can be readilyprepared from the DNA sequences using any of a variety of expressionvectors known to those of ordinary skill in the art. Expression may beachieved in any appropriate host cell that has been transformed ortransfected with an expression vector containing a DNA molecule thatencodes a recombinant polypeptide. Suitable host cells includeprokaryotes, yeast and higher eukaryotic cells. Preferably the hostcells employed are E. coli, yeast or a mammalian cell line such as Cosor CHO. Supernatants from the soluble host/vector systems that secreterecombinant protein or polypeptide into culture media may be firstconcentrated using a commercially available filter. Followingconcentration, the concentrate may be applied to a suitable purificationmatrix such as an affinity matrix or an ion exchange resin. Finally, oneor more reverse phase HPLC steps can be employed to further purify arecombinant polypeptide.

Fragments and other variants having less than about 100 amino acids, andgenerally less than about 50 amino acids, may also be generated bysynthetic means, using techniques well known to those of ordinary skillin the art. For example, such polypeptides may be synthesized using anyof the commercially available solid-phase techniques, such as theMerrifield solid-phase synthesis method, wherein amino acids aresequentially added to a growing amino acid chain (Merrifield, 1963, J.Am. Chem. Soc. 85:2146-2149). Equipment for automated synthesis ofpolypeptides is commercially available from suppliers such as PerkinElmer/Applied BioSystems Division (Foster City, Calif.), and may beoperated according to the manufacturer's instructions.

Variants of the polypeptide for use in accordance with the invention canhave one or more amino acid substitutions, deletions, additions and/orinsertions in the amino acid sequence indicated that result in apolypeptide that retains the ability to elicit an immune response to HSVor HSV-infected cells. Such variants may generally be identified bymodifying one of the polypeptide sequences described herein andevaluating the reactivity of the modified polypeptide using a knownassay such as a T cell assay described herein. Polypeptide variantspreferably exhibit at least about 70%, more preferably at least about90%, and most preferably at least about 95% identity to the identifiedpolypeptides. These amino acid substitutions include, but are notnecessarily limited to, amino acid substitutions known in the art as“conservative”.

A “conservative” substitution is one in which an amino acid issubstituted for another amino acid that has similar properties, suchthat one skilled in the art of peptide chemistry would expect thesecondary structure and hydropathic nature of the polypeptide to besubstantially unchanged. Amino acid substitutions may generally be madeon the basis of similarity in polarity, charge, solubility,hydrophobicity, hydrophilicity and/or the amphipathic nature of theresidues. For example, negatively charged amino acids include asparticacid and glutamic acid; positively charged amino acids include lysineand arginine; and amino acids with uncharged polar head groups havingsimilar hydrophilicity values include leucine, isoleucine and valine;glycine and alanine; asparagine and glutamine; and serine, threonine,phenylalanine and tyrosine. Other groups of amino acids that mayrepresent conservative changes include: (1) ala, pro, gly, glu, asp,gin, asn, set, thr; (2) cys, ser, tyr, thr; (3) val, ile, leu, met, ala,phe; (4) lys, arg, his; and (5) phe, tyr, trp, his. A variant may also,or alternatively, contain nonconservative changes. In a preferredembodiment, variant polypeptides differ from a native sequence bysubstitution, deletion or addition of five amino acids or fewer.Variants may also (or alternatively) be modified by, for example, thedeletion or addition of amino acids that have minimal influence on theimmunogenicity, secondary structure and hydropathic nature of thepolypeptide.

Polynucleotides, Vectors, Host Cells and Recombinant Viruses

The invention provides polynucleotides that encode one or morepolypeptides of the invention. The polynucleotide can be included in avector. The vector can further comprise an expression control sequenceoperably linked to the polynucleotide of the invention. In someembodiments, the vector includes one or more polynucleotides encodingother molecules of interest. In one embodiment, the polynucleotide ofthe invention and an additional polynucleotide can be linked so as toencode a fusion protein.

Within certain embodiments, polynucleotides may be formulated so topermit entry into a cell of a mammal, and expression therein. Suchformulations are particularly useful for therapeutic purposes, asdescribed below. Those of ordinary skill in the art will appreciate thatthere ate many ways to achieve expression of a polynucleotide in atarget cell, and any suitable method may be employed. For example, apolynucleotide may be incorporated into a viral vector such as, but notlimited to, adenovirus, adeno-associated virus, tetrovirus, or vacciniaor other pox virus (e.g., avian pox virus). Techniques for incorporatingDNA into such vectors are well known to those of ordinary skill in theart. A retroviral vector may additionally transfer or incorporate a genefor a selectable marker (to aid in the identification or selection oftransduced cells) and/or a targeting moiety, such as a gene that encodesa ligand for a receptor on a specific target cell, to render the vectortarget specific. Targeting may also be accomplished using an antibody,by methods known to those of ordinary skill in the art.

The invention also provides a host cell transformed with a vector of theinvention. The transformed host cell can be used in a method ofproducing a polypeptide of the invention. The method comprises culturingthe host cell and recovering the polypeptide so produced. The recoveredpolypeptide can be purified from culture supernatant.

Vectors of the invention can be used to genetically modify a cell,either in vivo, ex vivo or in vitro. Several ways of geneticallymodifying cells are known, including transduction or infection with aviral vector either directly or via a retroviral producer cell, calciumphosphate precipitation, fusion of the recipient cells with bacterialprotoplasts containing the DNA, treatment of the recipient cells withliposomes or microspheres containing the DNA, DEAE dextran,receptor-mediated endocytosis, electroporation, micro-injection, andmany other techniques known to those of skill. See, e.g., Sambrook etal. Molecular Cloning—A Laboratory Manual (2nd ed.) 1-3, 1989; andCurrent Protocols in Molecular Biology, F. M. Ausubel et al., eds.,Greene Publishing Associates, Inc. and John Wiley & Sons, Inc., (1994Supplement).

Examples of viral vectors include, but are not limited to retroviralvectors based on, e.g., HIV, SIV, and murine retroviruses, gibbon apeleukemia virus and other viruses such as adeno-associated viruses (AAVs)and adenoviruses. (Miller et al. 1990, Mol. Cell Biol. 10:4239;J.Kolberg 1992, NIH Res. 4:43, and Cornetta et al. 1991, Hum. Gene Ther.2:215). Widely used retroviral vectors include those based upon murineleukemia virus (MuLV), gibbon ape leukemia virus (GaLV), ecotropicretroviruses, simian immunodeficiency virus (SIV), humanimmunodeficiency virus (HIV), and combinations. See, e.g. Buchscher etal. 1992, J. Virol. 66(5):2731-2739; Johann et al. 1992, J. Virol.66(5):1635-1640; Sommerfelt et al. 1990, Virol. 176:58-59; Wilson et al.1989, J. Virol. 63:2374-2378; Miller et al. 1991, J. Virol.65:2220-2224, and Rosenberg and Fauci 1993 in Fundamental Immunology,Third Edition, W. E. Paul (ed.) Raven Press, Ltd., New York and thereferences therein; Miller et al. 1990, Mol. Cell. Biol. 10:4239; R.Kolberg 1992, J. NIH Res. 4:43; and Cornetta et al. 1991, Hum. GeneTher. 2:215.

In vitro amplification techniques suitable for amplifying sequences tobe subcloned into an expression vector are known. Examples of such invitro amplification methods, including the polymerase chain reaction(PCR), ligase chain reaction (LCR), Qβ-replicase amplification and otherRNA polymerase mediated techniques (e.g., NASBA), are found in Sambrooket al. 1989, Molecular Cloning—A Laboratory Manual (2nd Ed) 1-3; andU.S. Pat. No. 4,683,202; PCR Protocols A Guide to Methods andApplications (Innis et al. eds.) Academic Press Inc. San Diego, Calif.1990. Improved methods of cloning in vitro amplified nucleic acids aredescribed in U.S. Pat. No. 5,426,039.

The invention additionally provides a recombinant microorganismgenetically modified to express a polynucleotide of the invention. Therecombinant microorganism can be useful as a vaccine, and can beprepared using techniques known in the art for the preparation of liveattenuated vaccines. Examples of microorganisms for use as live vaccinesinclude, but are not limited to, viruses and bacteria. In a preferredembodiment, the recombinant microorganism is a virus. Examples ofsuitable viruses include, but are not limited to, vaccinia virus, canarypox virus, retrovirus, lentivirus, HSV and adenovirus.

Compositions

The invention provides compositions that are useful for treating andpreventing HSV infection. The compositions can be used to inhibit viralreplication and to kill virally-infected cells. In one embodiment, thecomposition is a pharmaceutical composition. The composition cancomprise a therapeutically or prophylactically effective amount of apolypeptide, polynucleotide, recombinant virus, APC or immune cell ofthe invention. An effective amount is an amount sufficient to elicit oraugment an immune response, e.g., by activating T cells. One measure ofthe activation of T cells is a cytotoxicity assay, as described in D. M.Koelle et al., 1997, Human Immunol. 53:195-205. In some embodiments, thecomposition is a vaccine.

The composition can optionally include a carrier, such as apharmaceutically acceptable carrier. Pharmaceutically acceptablecarriers are determined in part by the particular composition beingadministered, as well as by the particular method used to administer thecomposition. Accordingly, there is a wide variety of suitableformulations of pharmaceutical compositions of the present invention.Formulations suitable for parenteral administration, such as, forexample, by intraarticular (in the joints), intravenous, intramuscular,intradermal, intraperitoneal, and subcutaneous routes, and carriersinclude aqueous isotonic sterile injection solutions, which can containantioxidants, buffers, bacteriostats, and solutes that render theformulation isotonic with the blood of the intended recipient, andaqueous and non-aqueous sterile suspensions that can include suspendingagents, solubilizers, thickening agents, stabilizers, preservatives,liposomes, microspheres and emulsions.

The composition of the invention can further comprise one or moreadjuvants. Examples of adjuvants include, but are not limited to, helperpeptide, alum, Freund's, muramyl tripeptide phosphatidyl ethanolamine oran immunostimulating complex, including cytokines. In some embodiments,such as with the use of a polynucleotide vaccine, an adjuvant such as ahelper peptide or cytokine can be provided via a polynucleotide encodingthe adjuvant. Vaccine preparation is generally described in, forexample, M. F. Powell and M. J. Newman, eds., “Vaccine Design (thesubunit and adjuvant approach),” Plenum Press (NY, 1995). Pharmaceuticalcompositions and vaccines within the scope of the present invention mayalso contain other compounds, which may be biologically active orinactive. For example, one or more immunogenic portions of other viralantigens may be present, either incorporated into a fusion polypeptideor as a separate compound, within the composition or vaccine. Apharmaceutical composition or vaccine may contain DNA encoding one ormore of the polypeptides of the invention, such that the polypeptide isgenerated in situ. As noted above, the DNA may be present within any ofa variety of delivery systems known to those of ordinary skill in theart, including nucleic acid expression systems, bacteria and viralexpression systems. Numerous gene delivery techniques axe well known inthe art, such as those described by Rolland, 1998, Crit. Rev. Therap.Drug Carrier Systems 15:143-198, and references cited therein.Appropriate nucleic acid expression systems contain the necessary DNAsequences for expression in the patient (such as a suitable promoter andterminating signal). Bacterial delivery systems involve theadministration of a bacterium (such as Bacillus-Calmette-Guerrin) thatexpresses an immunogenic portion of the polypetide on its cell surfaceor secretes such an epitope. In a preferred embodiment, the DNA may beintroduced using a viral expression system (e.g., vaccinia or other poxvirus, retrovirus, or adenovirus), which may involve the use of anon-pathogenic (defective), replication competent virus. Suitablesystems are disclosed, for example, in Fisher-Hoch et al., 1989, Proc.Natl. Acad. Sci. USA 86:317-321; Moss and Flexner, 1989, Ann. N.Y. Acad.Sci. 569:86-103; Flexner et al., 1990, Vaccine 8:17-21; U.S. Pat. Nos.4,603,112, 4,769,330, and 5,017,487; WO 89/01 973; U.S. Pat. No.4,777,127; GB 2,200,651; EP 0,345,242; WO 91102805; Berkner, 1988,Biotechniques 6:616-627; Rosenfeld et al., 1991, Science 252:431-434;Kolls et at, 1994, Proc. Natl. Acad. Sci. USA 91:215-219; Kass-Eisler etat, 1993, Proc. Natl. Acad. Sci. USA 90:11498-11502; Guzman et al.,1993, Circulation 88:2838-2848; and Guzman et al., 1993, Cir. Res.73:1202-1207. Techniques for incorporating DNA into such expressionsystems are well known to those of ordinary skill in the art. The DNAmay also be “naked,” as described, for example, in Ulmer et al., 1993,Science 259:1745-1749 and reviewed by Cohen, 1993, Science259:1691-1692. The uptake of naked DNA may be increased by coating theDNA onto biodegradable beads, which are efficiently transported into thecells.

While any suitable carrier known to those of ordinary skill in the artmay be employed in the pharmaceutical compositions of this invention,the type of carrier will vary depending on the mode of administration.Compositions of the present invention may be formulated for anyappropriate manner of administration, including for example, topical,oral, nasal, intravenous, intracranial, intraperitoneal, subcutaneous orintramuscular administration. For parenteral administration, such assubcutaneous injection, the carrier preferably comprises water, saline,alcohol, a fat, a wax or a buffer. For oral administration, any of theabove carriers or a solid carrier, such as mannitol, lactose, starch,magnesium stearate, sodium saccharine, talcum, cellulose, glucose,sucrose, and magnesium carbonate, may be employed. Biodegradablemicrospheres (e.g., polylactate polyglycolate) may also be employed ascarriers for the pharmaceutical compositions of this invention. Suitablebiodegradable microspheres are disclosed, for example, in U.S. Pat. Nos.4,897,268 and 5,075,109.

Such compositions may also comprise buffers (e.g., neutral bufferedsaline or phosphate buffered saline), carbohydrates (e.g., glucose,mannose, sucrose or dextrans), mannitol, proteins, polypeptides or aminoacids such as glycine, antioxidants, chelating agents such as EDTA orglutathione, adjuvants (e.g., aluminum hydroxide) and/or preservatives.Alternatively, compositions of the present invention may be formulatedas a lyophilizate. Compounds may also be encapsulated within liposomesusing well known technology.

Any of a variety of adjuvants may be employed in the vaccines of thisinvention. Most adjuvants contain a substance designed to protect theantigen from rapid catabolism, such as aluminum hydroxide or mineraloil, and a stimulator of immune responses, such as lipid A, Bortadellapertussis or Mycobacterium tuberculosis derived proteins. Suitableadjuvants are commercially available as, for example, Freund'sIncomplete Adjuvant and Complete Adjuvant (Difco Laboratories, Detroit,Mich.); Merck Adjuvant 65 (Merck and Company, Inc., Rahway, N.J.);aluminum salts such as aluminum hydroxide gel (alum) or aluminumphosphate; salts of calcium, iron or zinc; an insoluble suspension ofacylated tyrosine acylated sugars; cationically or anionicallyderivatized polysaccharides; polyphosphazenes biodegradablemicrospheres; monophosphoryl lipid A and quil A. Cytokines, such as GMCSF or interleukin-2, -7, or -12, may also be used as adjuvants.

Within the vaccines provided herein, the adjuvant composition ispreferably designed to induce an immune response predominantly of theTh1 type. High levels of Th1-type cytokines (e.g., IFN-γ, IL-2 andIL-12) tend to favor the induction of cell mediated immune responses toan administered antigen. In contrast, high levels of Th2-type cytokines(e.g., IL-4, IL-5, IL-6, IL-10 and TNF-β) tend to favor the induction ofhumoral immune responses. Following application of a vaccine as providedherein, a patient will support an immune response that includes Th1- andTh2-type responses. Within a preferred embodiment, in which a responseis predominantly Th1-type, the level of Th1-type cytokines will increaseto a greater extent than the level of Th2-type cytokines. The levels ofthese cytokines may be readily assessed using standard assays. For areview of the families of cytokines, see Mosmann and Coffman, 1989, Ann.Rev. Immunol. 7:145-173.

Preferred adjuvants for use in eliciting a predominantly Th1-typeresponse include, for example, a combination of monophosphoryl lipid A,preferably 3-de-O-acylated monophosphoryl lipid A (3D-MPL), togetherwith an aluminum salt. MPL™ adjuvants are available from CorixaCorporation (see U.S. Pat. Nos. 4,436,727; 4,877,611; 4,866,034 and4,912,094). CpG-containing oligonucleotides (in which the CpGdinucleotide is unmethylated) also induce a predominantly Th1 response.Such oligonucleotides are well known and are described, for example, inWO 96/02555. Another preferred adjuvant is a saponin, preferably QS21,which may be used alone or in combination with other adjuvants. Forexample, an enhanced system involves the combination of a monophosphoryllipid A and saponin derivative, such as the combination of QS21 and3D-MPL as described in WO 94/00153, or a less reactogenic compositionwhere the QS21 is quenched with cholesterol, as described in WO96/33739. Other preferred formulations comprises an oil-in-wateremulsion and tocopherol. A particularly potent adjuvant formulationinvolving QS21, 3D-MPL and tocopherol in an oil-in-water emulsion isdescribed in WO 95/17210. Another adjuvant that may be used is AS-2(Smith-Kline Beecham). Any vaccine provided herein may be prepared usingwell known methods that result in a combination of antigen, immuneresponse enhancer and a suitable carrier or excipient.

The compositions described herein may be administered as part of asustained release formulation (i.e., a formulation such as a capsule orsponge that effects a slow release of compound followingadministration). Such formulations may generally be prepared using wellknown technology and administered by, for example, oral, rectal orsubcutaneous implantation, or by implantation at the desired targetsite. Sustained-release formulations may contain a polypeptide,polynucleotide or antibody dispersed in a carrier matrix and/orcontained within a reservoir surrounded by a rate controlling membrane.Carriers for use within such formulations are biocompatible, and mayalso be biodegradable; preferably the formulation provides a relativelyconstant level of active component release. The amount of activecompound contained within a sustained release formulation depends uponthe site of implantation, the rate and expected duration of release andthe nature of the condition to be treated or prevented.

Any of a variety of delivery vehicles may be employed withinpharmaceutical compositions and vaccines to facilitate production of anantigen-specific immune response that targets HSV-infected cells.Delivery vehicles include antigen presenting cells (APCs), such asdendritic cells, macrophages, B cells, monocytes and other cells thatmay be engineered to be efficient APCs. Such cells may, but need not, begenetically modified to increase the capacity for presenting theantigen, to improve activation and/or maintenance of the T cellresponse, to have antiviral effects per se and/or to be immunologicallycompatible with the receiver (i.e., matched HLA haplotype). APCs maygenerally be isolated from any of a variety of biological fluids andorgans, including tumor and peritumotal tissues, and may be autologous,allogeneic, syngeneic or xenogeneic cells.

Certain preferred embodiments of the present invention use dendriticcells or progenitors thereof as antigen-presenting cells. Dendriticcells are highly potent APCs (Banchereau and Steinman, Nature392:245-251, 1998) and have been shown to be effective as aphysiological adjuvant for eliciting prophylactic or therapeuticimmunity (see Timmerman and Levy, Ann. Rev. Med. 50:507-529, 1999). Ingeneral, dendritic cells may be identified based on their typical shape(stellate in situ, with marked cytoplasmic processes (dendrites) visiblein vitro) and based on the lack of differentiation markers of B cells(CD19 and CD20), T cells (CD3), monocytes (CD14) and natural killercells (CD56), as determined using standard assays. Dendritic cells may,of course, be engineered to express specific cell-surface receptors orligands that are not commonly found on dendritic cells in vivo or exvivo, and such modified dendritic cells are contemplated by the presentinvention. As an alternative to dendritic cells, secreted vesiclesantigen-loaded dendritic cells (called exosomes) may be used within avaccine (Zitvogel et al., 1998, Nature Med. 4:594-600).

Dendritic cells and progenitors may be obtained from peripheral blood,bone marrow, tumor-infiltrating cells, peritumoral tissues-infiltratingcells, lymph nodes, spleen, skin, umbilical cord blood or any othersuitable tissue or fluid. For example, dendritic cells may bedifferentiated ex vivo by adding a combination of cytokines such asGM-CSF, IL-4, IL-13 and/or TNFα to cultures of monocytes harvested fromperipheral blood. Alternatively, CD34 positive cells harvested fromperipheral blood, umbilical cord blood or bone marrow may bedifferentiated into dendritic cells by adding to the culture mediumcombinations of GM-CSF, IL-3, TNFα, CD40 ligand, LPS, flt3 ligand and/orother compound(s) that induce maturation and proliferation of dendriticcells.

Dendritic cells are conveniently categorized as “immature” and “mature”cells, which allows a simple way to discriminate between two wellcharacterized phenotypes. However, this nomenclature should not beconstrued to exclude all possible intermediate stages ofdifferentiation. Immature dendritic cells are characterized as APC witha high capacity for antigen uptake and processing, which correlates withthe high expression of Fcγ receptor, mannose receptor and DEC-205marker. The mature phenotype is typically characterized by a lowerexpression of these markers, but a high expression of cell surfacemolecules responsible for T cell activation such as class I and class IIMHC, adhesion molecules (e.g., CD54 and CD11) and costimulatorymolecules (e.g., CD40, CD80 and CD86). APCs may generally be transfectedwith a polynucleotide encoding a polypeptide (or portion or othervariant thereof) such that the polypeptide, or an immunogenic portionthereof, is expressed on the cell surface. Such transfection may takeplace ex vivo, and a composition or vaccine comprising such transfectedcells may then be used for therapeutic purposes, as described herein.Alternatively, a gene delivery vehicle that targets a dendritic or otherantigen presenting cell may be administered to a patient, resulting intransfection that occurs in vivo. In vivo and ex vivo transfection ofdendritic cells, for example, may generally be performed using anymethods known in the art, such as those described in WO 97/24447, or thegene gun approach described by Mahvi et al., 1997, Immunology and CellBiology 75:456-460. Antigen loading of dendritic cells may be achievedby incubating dendritic cells or progenitor cells with the tumorpolypeptide, DNA (naked or within a plasmid vector) or RNA; or withantigen-expressing recombinant bacterium or viruses (e.g., vaccinia,fowlpox, adenovirus or lentivirus vectors). Prior to loading, thepolypeptide may be covalently conjugated to an immunological partnerthat provides T cell help (e.g., a carrier molecule). Alternatively, adendritic cell may be pulsed with a non-conjugated immunologicalpartner, separately or in the presence of the polypeptide.

Administration of the Compositions

Treatment includes prophylaxis and therapy. Prophylaxis or treatment canbe accomplished by a single direct injection at a single time point ormultiple time points. Administration can also be nearly simultaneous tomultiple sites. Patients or subjects include mammals, such as human,bovine, equine, canine, feline, porcine, and ovine animals. Preferably,the patients or subjects are human.

Compositions are typically administered in vivo via parenteral (e.g.intravenous, subcutaneous, and intramuscular) or other traditionaldirect routes, such as buccal/sublingual, rectal, oral, nasal topical(such as transdermal and ophthalmic), vaginal, pulmonary, intraarterial,intraperitoneal, intraocular, or intranasal routes or directly into aspecific tissue.

The compositions are administered in any suitable manner, often withpharmaceutically acceptable carriers. Suitable methods of administeringcells in the context of the present invention to a patient areavailable, and, although more than one route can be used to administer aparticular cell composition, a particular route can often provide a moreimmediate and more effective reaction than another route.

The dose administered to a patient, in the context of the presentinvention should be sufficient to effect a beneficial therapeuticresponse in the patient over time, or to inhibit infection or diseasedue to infection. Thus, the composition is administered to a patient inan amount sufficient to elicit an effective immune response to thespecific antigens and/or to alleviate, reduce, cure or at leastpartially arrest symptoms and/or complications from the disease orinfection. An amount adequate to accomplish this is defined as a“therapeutically effective dose.”

The dose will be determined by the activity of the composition producedand the condition of the patient, as well as the body weight or surfaceareas of the patient to be treated. The size of the dose also will bedetermined by the existence, nature, and extent of any adverse sideeffects that accompany the administration of a particular composition ina particular patient. In determining the effective amount of thecomposition to be administered in the treatment or prophylaxis ofdiseases such as HSV infection, the physician needs to evaluate theproduction of an immune response against the virus, progression of thedisease, and any treatment-related toxicity.

For example, a vaccine or other composition containing a subunit HSVprotein can include 1-10,000 micrograms of HSV protein per dose. In apreferred embodiment, 10-1000 micrograms of HSV protein is included ineach dose in a more preferred embodiment 10-100 micrograms of HSVprotein dose. Preferably, a dosage is selected such that a single dosewill suffice or, alternatively, several doses are administered over thecourse of several months. For compositions containing HSVpolynucleotides or peptides, similar quantities are administered perdose.

In one embodiment, between 1 and 10 doses may be administered over a 52week period. Preferably, 6 doses are administered, at intervals of 1month, and booster vaccinations may be given periodically thereafter.Alternate protocols may be appropriate for individual patients. Asuitable dose is an amount of a compound that, when administered asdescribed above, is capable of promoting an antiviral immune response,and is at least 10-50% above the basal (i.e., untreated) level. Suchvaccines should also be capable of causing an immune response that leadsto an improved clinical outcome in vaccinated patients as compared tonon-vaccinated patients. In general, for pharmaceutical compositions andvaccines comprising one or more polypeptides, the amount of eachpolypeptide present in a dose ranges from about 0.1 μg to about 5 mg perkg of host. Preferably, the amount ranges from about 10 to about 1000 μgper dose. Suitable volumes for administration will vary with the size,age and immune status of the patient, but will typically range fromabout 0.1 mL to about 5 mL, with volumes less than about 1 mL being mostcommon.

Compositions comprising immune cells are preferably prepared from immunecells obtained from the subject to whom the composition will beadministered. Alternatively, the immune cells can be prepared from anHLA-compatible donor. The immune cells are obtained from the subject ordonor using conventional techniques known in the art, exposed to APCsmodified to present an epitope of the invention, expanded ex vivo, andadministered to the subject. Protocols for ex vivo therapy are describedin Rosenberg et al., 1990, New England J. Med. 9:570-578. In addition,compositions can comprise APCs modified to present an epitope of theinvention.

Immune cells may generally be obtained in sufficient quantities foradoptive immunotherapy by growth in vitro, as described herein. Cultureconditions for expanding single antigen-specific effector cells toseveral billion in number with retention of antigen recognition in vivoare well known in the art. Such in vitro culture conditions typicallyuse intermittent stimulation with antigen, often in the presence ofcytokines (such as IL-2) and non-dividing feeder cells. As noted above,immunoreactive polypeptides as provided herein may be used to enrich andrapidly expand antigen-specific T cell cultures in order to generate asufficient number of cells for immunotherapy. In particular,antigen-presenting cells, such as dendritic, macrophage, monocyte,fibroblast and/or B cells, may be pulsed with immunoreactivepolypeptides or transfected with one or more polynucleotides usingstandard techniques well known in the art. For example,antigen-presenting cells can be transfected with a polynucleotide havinga promoter appropriate for increasing expression in a recombinant virusor other expression system. Cultured effector cells for use in therapymust be able to grow and distribute widely, and to survive long term invivo. Studies have shown that cultured effector cells can be induced togrow in vivo and to survive long term in substantial numbers by repeatedstimulation with antigen supplemented with IL-2 (see, for example,Cheever et al., 1997, Immunological Reviews 157:177).

Administration by many of the routes of administration described hereinor otherwise known in the art may be accomplished simply by directadministration using a needle, catheter or related device, at a singletime point or at multiple time points.

In Vivo Testing of Identified Antigens

Conventional techniques can be used to confirm the in vivo efficacy ofthe identified HSV antigens. For example, one technique makes use of amouse challenge model. Those skilled in the art, however, willappreciate that these methods are routine, and that other models can beused.

Once a compound or composition to be tested has been prepared, the mouseor other subject is immunized with a series of injections. For exampleup to 10 injections can be administered over the course of severalmonths, typically with one to 4 weeks elapsing between doses. Followingthe last injection of the series, the subject is challenged with a doseof virus established to be a uniformly lethal dose. A control groupreceives placebo, while the experimental group is actively vaccinated.Alternatively, a study can be designed using sublethal doses.Optionally, a dose-response study can be included. The end points to bemeasured in this study include death and severe neurological impairment,as evidenced, for example, by spinal cord gait. Survivors can also besacrificed for quantitative viral cultures of key organs includingspinal cord, brain, and the site of injection. The quantity of viruspresent in ground up tissue samples can be measured. Compositions canalso be tested in previously infected animals for reduction inrecurrence to confirm efficacy as a therapeutic vaccine.

Efficacy can be determined by calculating the IC₅₀, which indicates themicrograms of vaccine per kilogram body weight required for protectionof 50% of subjects from death. The IC₅₀ will depend on the challengedose employed. In addition, one can calculate the LD₅₀, indicating howmany infectious units are required to kill one half of the subjectsreceiving a particular dose of vaccine. Determination of the post mortemviral titer provides confirmation that viral replication was limited bythe immune system.

A subsequent stage of testing would be a vaginal inoculation challenge.For acute protection studies, mice can be used. Because they can bestudied for both acute protection and prevention of recurrence, guineapigs provide a more physiologically relevant subject for extrapolationto humans. In this type of challenge, a nonlethal dose is administered,the guinea pig subjects develop lesions that heal and recur. Measurescan include both acute disease amelioration and recurrence of lesions.The intervention with vaccine or other composition can be providedbefore or after the inoculation, depending on whether one wishes tostudy prevention versus therapy.

Methods

The invention provides a method for treatment and/or prevention of HSVinfection in a subject. The method comprises administering to thesubject a composition of the invention. The composition can be used as atherapeutic or prophylactic vaccine. In one embodiment, the HSV isHSV-2. Alternatively, the HSV is HSV-1. The invention additionallyprovides a method for inhibiting HSV replication, for killingHSV-infected cells, for increasing secretion of lymphokines havingantiviral and/or immunomodulatory activity, and for enhancing productionof herpes-specific antibodies. The method comprises contacting anHSV-infected cell with an immune cell directed against an antigen of theinvention, for example, as described in the Examples presented herein.The contacting can be performed in vitro or in vivo. In a preferredembodiment, the immune cell is a T cell. T cells include CD4 and CD8 Tcells. Compositions of the invention can also be used as a tolerizingagent against immunopathologic disease.

In addition, the invention provides a method of producing immune cellsdirected against HSV. The method comprises contacting an immune cellwith an antigen-presenting cell, wherein the antigen-presenting cell ismodified to present an antigen included in a polypeptide of theinvention. Preferably, the antigen-presenting cell is a dendritic cell.The cell can be modified by, for example, peptide loading or geneticmodification with a nucleic acid sequence encoding the polypeptide. Inone embodiment, the immune cell is a T cell. T cells include CD4 and CD8T cells. Also provided are immune cells produced by the method. Theimmune cells can be used to inhibit HSV replication, to killHSV-infected cells, in vitro or in vivo, to increase secretion oflymphokines having antiviral and/or immunomodulatory activity, toenhance production of herpes-specific antibodies, or in the treatment orprevention of HSV infection in a subject.

The invention provides methods for identifying immunogenic epitopesassociated with infectious organisms. In one embodiment, the methodcomprises preparing a collection of random fragments of the organismalgenome. The preparing can comprise digesting the entire genome, althoughit is not necessary to begin with the full genome. The digestingpreferably comprises contacting the genome with one or more restrictionenzymes to obtain a collection of random fragments having a desiredrange of lengths. Alternatively, one can sonicate, nebulize or otherwisetreat material containing the genome of interest and isolate from a gelfragments of an appropriate size.

The digesting, and the selection of restriction enzymes, is designed toobtain fragments of the genome that are longer than the average lengthof a T cell epitope, e.g., greater than about 30 nucleotides in length.Preferably, the fragments are small enough such that genetic stops areinfrequent, e.g., about 200 to about 500 base pairs in length. Where thegenomic sequence or a restriction map of an organism of interest isknown, one can analyze the genome to identify restriction sites that, iftargeted with the appropriate restriction enzymes, will result in thedesired number of fragments of an appropriate length. The restrictionenzymes can also be selected to target sites that are compatible withsites in a cloning vector to be used.

The random fragments can then be used to express polypeptides encoded bythe fragments. The fragments can be expressed individually, orpreferably, as a pool of polypeptides, either alone or as fusionproteins. Those skilled in the art will appreciate that polypeptides canbe expressed from either DNA or RNA as a starting material. For example,expression of polypeptides from RNA viruses can be achieved by firstpreparing a cDNA from the RNA fragment, and then using the cDNA toexpress the polypeptide.

The polypeptide can be expressed from a vector containing the fragmentof genome. In a preferred embodiment, the vector is a plasmid, such as apcDNA3.1(+)his vector. Those skilled in the art will appreciate thatother vectors can be used that are capable of expressing polypeptidefrom an insert. Preferably, the polypeptide is expressed as a fusionprotein. In one embodiment, the expressing comprises culturing a hostcell transfected or transduced with a vector containing the fragment ofgenome. In a preferred embodiment of the method, fragments are ligatedinto expression vectors in the three different reading frames, and inboth directions, to make a library.

The quality of the library can be improved by ligating the genomicfragments using a partial fill-in reaction. For example, the sticky endscreated by digestion of HSV-2 with Sau3A I can result in ligation ofmultiple viral fragments to one another and in a variety oforientations. A partial fill-in reaction can be used to modify thesticky ends such that the fragments of viral genome will not ligate toeach other, and only one viral insert will be present in each vector.This results in a library that is simpler and less time-consuming toanalyze.

The method further comprises assaying the ability of the expressedpolypeptide to elicit an immune response. The ability to elicit animmune response is indicative of the presence of an immunogenic epitopewithin the polypeptide. In one embodiment, the immune response is acellular immune response. The assaying can comprise performing an assaythat measures T cell stimulation or activation. Examples of T cellsinclude CD4 and CD8 T cells.

One example of a T cell stimulation assay is a cytotoxicity assay, suchas that described in Koelle, D M et al., Human Immunol. 1997,53;195-205. In one example, the cytotoxicity assay comprises contactinga cell that presents the antigenic viral peptide in the context of theappropriate HLA molecule with a T cell, and detecting the ability of theT cell to kill the antigen presenting cell. Cell killing can be detectedby measuring the release of radioactive ⁵¹Cr from the antigen presentingcell. Release of ⁵¹Cr into the medium from the antigen presenting cellis indicative of cell killing. An exemplary criterion for increasedkilling is a statistically significant increase in counts per minute(cpm) based on counting of ⁵¹Cr radiation in media collected fromantigen presenting cells admixed with T cells as compared to controlmedia collected from antigen presenting cells admixed with media.

The assay can be performed on pools of polypeptides to identify poolscontaining active moieties. Further assays can then be performed onincreasingly smaller subsets of the original pools to isolatepolypeptides of interest. The material containing a fragment ofinterest, e.g., a plasmid with its viral insert, can be purified and theviral fragment sequenced. Based on the obtained sequence information,synthetic peptides can be prepared for subsequent testing andconfirmation of the identified antigens. Sequencing of fragments canalso lead to the identification of novel genes. The foregoing methodsteps can be repeated, wherein subfragments of the genome fragments areprepared. Increasingly smaller fragments can be expressed and tested todetermine the minimal epitope.

The method of the invention can be applied to a variety of infectiousorganisms, including bacteria, parasites and viruses. Preferred virusesare those containing intronless DNA or mostly coding sequence. Examplesof viruses include double-stranded DNA viruses, single-stranded DNAviruses, double-stranded RNA viruses and single-stranded RNA viruses.Examples of double-stranded DNA viruses include, but are not limited to,Epstein-Barr virus (EBV), cytomegalovirus (CMV), herpes simplex virus-1(HSV-1), HSV-2, varicella-zoster virus (VZV), human herpes virus-6(HHV-6), HHV-7, HHV-8, poxvirus and adenovirus. Examples ofsingle-stranded DNA viruses include, but are not limited to, parvovirus.Examples of double-stranded RNA viruses include, but are not limited to,retroviruses and reoviruses. Examples of single-stranded RNA virusesinclude, but are not limited to, paramyxoviruses, myxoviruses, andflaviviruses.

Because the method does not require knowledge of the organism's nucleicacid sequence, it provides a strategy for combating infectious organismsthat display a great deal of biological variability (e.g., HIV and HCV).For viruses exhibiting high variability, it is advantageous to use asource of viral nucleic acid material derived from a particular patient,a particular site (e.g., blood, skin, cervix) or representative viralstrain circulating in a particular geographical region or patientpopulation, which may differ from prototypical strains of known nucleicacid sequence.

In a preferred embodiment, the organism is HSV-2 and the fragments ofviral genome are prepared by digestion with Sau3A I. Examples of otherrestriction enzymes that can be used include, but are not limited to,Apa I, Sma I, and Alu I. The fragments of genomic DNA are then ligatedinto a vector, preferably by using a partial fill-in reaction (see 1999Stratagene catalog, page 56). A preferred vector is a member of thepcDNA3.1(+) his series. The fragments are then expressed usingconventional techniques. Preferably, the expression is performed using aCos-7 transfection method (De Plaen E et al. In: Lefkowits I, ed.Immunology Methods Manual, v. 2. New York: Academic Press,1997:691-718).

The host cell can be co-transfected with a nucleic acid molecule, suchas cDNA, encoding a relevant HLA molecule, such as an HLA heavy chain.The HLA molecule enables a host cell from a species (e.g., monkey in thecase of Cos cells) differing from that of the T cell source to recognizethe antigen derived from the infectious agent. The HLA molecule isselected to match the HLA molecule capable of presenting the targetantigen. Methods for identifying the appropriate HLA molecule aredescribed in Koelle, D M et al., J. Infectious Dis. 1994, 169:956-961;and DePlaen, E et al. In Immunology Methods Manual, 1997, AcademicPress, 704-705. In the absence of a definitive identification of thepresenting HLA molecule, cDNA encoding two or more candidate class I HLAmolecules can be co-transfected.

The ability of the expressed polypeptide to elicit a cellular immuneresponse is then assayed. Ability to elicit a cellular immune responseis indicative of the presence of an immunogenic epitope. Assays that canbe used to detect ability to elicit a cellular immune response include,but are not limited to, cytotoxicity assays and lymphokine secretionassays. In one embodiment, the assay is an interferon-gamma assay.

In a preferred embodiment, the invention provides a method foridentifying HSV epitopes immunogenic for CD8+ T cells. The methodcomprises obtaining CD8+ T cells from an HSV lesion, and assaying theobtained T cells to identify T cells having ability to recognizeHSV-infected cells. The method further comprises obtaining andfragmenting a nucleic acid preparation from HSV, expressing one or morefragments of the obtained nucleic acid, and assaying the expressedfragments for antigenic reactivity with the identified HSV-specific Tcells. An expressed fragment having reactivity with the HSV-specific Tcells is identified as encoding an HSV epitope immunogenic for CD8+ Tcells.

The invention also provides a diagnostic assay. The diagnostic assay canbe used to identify the immunological responsiveness of a patientsuspected of having a herpetic infection and to predict responsivenessof a subject to a particular course of therapy. The assay comprisesexposing T cells of a subject to an antigen of the invention, in thecontext of an appropriate APC, and testing for immunoreactivity by, forexample, measuring IFNγ, proliferation or cytotoxicity. Suitable assaysare described in more detail in the Examples.

EXAMPLES

The following examples are presented to illustrate the present inventionand to assist one of ordinary skill in making and using the same. Theexamples are not intended in any way to otherwise limit the scope of theinvention.

Example 1 Detection of HSV-specific CD8 CTL in Recurrent Genital HSV-2Lesions

This example demonstrates that specific CD8 CTL localize to genitalHSV-2 lesions. This is shown by serial lesion biopsy studies ofrecurrent genital HSV-2 lesions using cells that have encounteredantigen/APC in situ and are not restimulated with antigen in vitro priorto readout assays.

Materials & Methods

Lesion-infiltrating lymphocytes (LIL) were expanded for one cycle withphytohemaglutinin (PHA) and IL-2 in the presence of 50 μM acyclovir(ACV). Typically, 5×10^(6-5×10) ⁷ cells were obtained after two weeks.The phenotype of these bulk populations has been described (Koelle D Met al., J. Clin. Invest. 1998;101:1500-1508). Among TCR αβ, CD3+ cells,there is a gradual shift to CD8 predominance as lesions mature andcultures become negative.

Results

The local response had high levels of NK-cell activity as determined bylysis of K562 and allogeneic, HSV-2 infected lymphocyte continuous line(LCL) as early as day two of symptoms. NK cells were selectivelyenriched in cells expanded from lesions compared to normal skin.HSV-specific CD4 cells were similarly enriched early. Lesions wereenriched in both “Th1” (interferon-gamma (IFN-γ), IL-12 p40, IL-2) and“Th2” (IL-4, IL-5, IL-10, IL-13) mRNAs (Van Voorhis W C et al., J.Infect. Dis. 1996;173:491-95). The cytokine pattern oflesion-infiltrating HSV-2-specific CD8 CTL includes interferon-gamma.

In contrast to CD4 and NK activities, HSV-specific CTL infiltratedrecurrent HSV-2 genital lesion at later times (typically days 5-9) andtheir presence correlated with virus clearance (Koelle D M et al., J.Clin. Invest. 1998;101:1500-1508). The CD4 and CD8 components werestudied by subtracting NK and then either CD4 or CD8 cells. CTL activitywas observed in either CD8 cells alone or in both subsets.EBV-transformed LCL (Tigges M A et al., J. Virol. 1992;66:1622-34) wereused as target cells in CTL assays because autologous cells areconveniently made, HSV undergoes complete lytic replication in thesecells, and high levels of HLA and co-stimulatory/adhesion molecules arepresent.

HSV-specific CD8 clones (Table 1) have been isolated from herpeticvesicle fluid (Koelle D M et al., J. Infect. Dis. 1994;169:956-61) andlesions (Koelle D M et al., J. Clin. Invest. 1998;101:1500-1508).Secondary restimulation with antigen was not used. Many (>1,000)microcultures of CD8-enriched cells were cloned at 0.3-2 cells/well bystandard methods (Koelle D M et al., J. Clin. Invest.1998;101:1500-1508) and ˜200 clones were screened in CTL assays againstautologous LCL with and without 18 hour infection with HSV-2(multiplicity of infection, or MOI, 10). All clones were CD3/8/TCR αβ(+) and CD4/TCR γδ (−) by flow cytometry.

TABLE 1 Cytolytic activity of CD8 T cell clones (TCC) from recurrentHSV-2 lesions. Lysis is percent specific release at an effector:target(E:T) ratio of 20:1 or lower. Sub- Bx % specific lysis Epitope HLA jectDate TCC Mock HSV-1 HSV-2 location¹ restriction² RW 1997 51  0 1 87 0.0-0.12 B*4501 RW 1991 22³ 0 2 54 0.66-0.72 A*0201 ¹Location ofepitope within standard map (Dolan A et al., J. Virol. 1998; 72:2010-21)of HSV-2 genome; epitope mapping for HSV-2 type-specific TCC uses HSV-1× HSV-2 intertypic recombinant viruses (IRV) (Preston V G et al., J.Virol. 1978; 28:499-517) as described (Koelle D M et al., J. Virol.1994; 68:2803-10; Koelle D M et al., J. Virol. 1998; 72:7476-83).Boundaries are approximate. ²HLA allele restricting killing of HSV-2infected, partially matched LCL as described (Koelle D M et al., J.Infect. Dis. 1994; 169:956-61); serologic or DNA definitions aspermitted by method of typing. ³dkRW22. RW22 and RW.1991.22 refer to a Tcell clone derived from subject RW in 1991. Two clones given thedesignation “22” were separately derived from RW in 1991. Throughoutthis application, the two separately derived clones are distinguished bydkRW22 and cpRW22.

To measure diversity of the CD8 response, TCR Vβ analysis was performedon bulk, positively selected CD8+ cells from LIL expanded one cycle withPHA (the source culture for CD8 CTL clone RW51, Table 1 and below), aswell as CD8 cells from PBMC from the same donor. Total RNA (ChomczynskiP et al., in: Coligan J E et al., eds. Current Protocols in Immunology.New York: John Wiley and Sons, 1992:10.11.7-10.11.14) was reversetranscribed with oligo-dT primer and MMLV RT (Pharmacia). cDNA was usedin 24 separate PCR reactions with Cβ primer and family-specific Vβprimers. After 30 cycles of PCR, an aliquot of each reaction was mixedwith a fluorescent-labeled internal cβ primer and PCR continued for fivecycles to label amplimers of rearranged TCRVβ genes. Primers andprotocols were as described in Pannetier C et al., in: Oksenberg J R,ed. The antigen T cell receptor: selected protocols and applications.New York: Chapman and Hall, 1998: Section 9. Analysis by ABI sequencerwith fluorescent MW markers was done at the Biotechnology Core at FredHutchinson Cancer Research Center (Seattle, Wash.). The CD8 PBMC werevery polyclonal as judged by the Poisson distribution and multiple peakswithin the TCR Vβ amplimer “ladders” (FIG. 1A), while the lesion CD8population appeared to be quite oligoclonal (FIG. 1B). Similar resultswere obtained for another donor. These data are consistent with limiteddiversity of the local CD8 response in HSV-2 lesions.

Example 2 Detection of HSV-specific T-Cell Responses in CervicalLymphocytes

Mucosal immune responses are segregated from PBMC, and localization ofHSV-specific CTL to the mucosa of mice is associated with protectionfrom vaginal inoculation. This example demonstrates that HSV-specific Tcells, including CD8+ cells, can be detected in cervical lymphocytes.

Cells from a representative cervical cytobrush specimen were collectedduring an active genital HSV-2 outbreak and expanded in bulk withPHA/IL-2, and subsequently analyzed for HSV-specific proliferative (FIG.2A) and cytotoxic responses (FIG. 2B). Proliferation and cytotoxicityassays used autologous PBMC or LCL as APC as described above forskin-derived lymphocytes. Anti-HLA class I mAb W6/32 or anti-HLA DR mabL243 were used as described (Koelle D M et al., J. Virol. 1994,68:2803-10; Koelle D M et al., J. Infect. Dis. 1994, 169:956-61).Antigen-specific proliferative responses and cytotoxic responses werepresent. Fractionation and mAb inhibition studies show a contribution ofCD8 CTL to the cytotoxic response.

Example 3 Detection of HSV-specific T-Cell Responses in Primary GenitalHSV-2 Lesions

In this example, biopsy specimens were collected from a patientpresenting with symptoms consistent with primary genital HSV-2infection. The phenotypes of the collected cells were determined, andLIL and PBMC from the specimens were subjected to proliferative andcytotoxicity assays. The results show that the HSV-specificproliferative and cytotoxic responses of CTL present in primary genitalHSV-2 lesions are typical of those detected during recurrent disease.

CW7477 developed dysuria, fever, buttock, and lower abdomen lesionsthree days after his last sexual contact. Lesions lasted 13 days andgrew HSV-2. Acyclovir treatment was begun on day four of symptoms.Biopsies were done on days four and seven. Serostatus was atypicalpositive (only a few bands present on immunoblot) at day four, with morebands, but still less than most convalescent sera, on day 26, byenhanced chemiluminescence (ECL; Dalessio J. and Ashley R., J. Clin.Microbiol. 1992, 30(4):1005-7) variant of type-specific HSV-2immunoblot. The clinical and laboratory data were consistent withprimary genital HSV-2 infection. Biopsy specimens were obtained on dayfour and seven of symptoms and bulk LIL expanded with PHA/IL-2 asdescribed above.

The phenotype of the expanded cells was split between CD4 and CD8 cells,with 15-25% CD3+/CD16,56+ cells and 5-10% TCR γδ+ cells in the LIL. Incomparison, cells from normal skin had almost no CD16,56 (+) events andno TCR γδ cells. The nature of the CD3+/CD16,56+ cells is unknown butthese are frequently seen in expanded LIL. The antibody cocktail has acombination of αCD16-PE and αCD56-PE.

TABLE 2 Functional activity of bulk LIL or PBMC from human primarygenital HSV-2 infection proliferation¹ cytotoxicity² responder effectorday 4 day 4 day 4 day 4 day 7 normal day 15 day 4 day 7 normal lesionantigen lesion lesion skin PBMC target lesion lesion skin CD8+ media 203587 153 1,092 au mock 2.9 2.2 4.3 1.1 mock 187 775 146 1,296 au HSV-116.2 28.3 2.9 virus 1:100 UV HSV-1 12,926 26,328 143 au HSV-2 48.3 29.84.4 67.5 1:100 UV HSV-2 12,685 14,481 152 20,179 au vac wt −2.5 4.8 2.31:100 gB2 16,416 23,351 234 15,282 au vgB2 15.8 16.8 −5.2 1 μg/ml gD28,750 13,392 216 3,976 au vgD2 5.1 13.1 2.1 1 μg/ml VP16 816 8,689 166au 3.0 6.6 2.1 1 μg/ml vVP16 PHA 12,795 22,318 41,229 59,691 al mock 1.05.9 2.8 0.8 μg/ml al HSV-2 3.6 4.5 2.7 K562 1.1 69.2 2.1 10.4 ¹Bulkcells were used at 10⁴/well with autologous irradiated PBMC (10⁵/well)as APC. Results are mean cpm ³H thymidine incorporation on day 4. Day 15PBMC used at 10⁵ live cells/well. ²Bulk cells used at 20:1effector:target ratio in ⁵¹Cr release versus autologous (au) or HLAmismatched (al) LCL infected 18 h., MOI 10 as indicated (v = vaccinia).CD8+ cells enriched by MidiMacs ™ (Miltenyi). Results are % specificrelease; spontaneous release < 22%.

The HSV-specific proliferative and cytotoxic responses were fairlytypical of those detected during recurrent disease (Koelle D M et al.,J.Clin. Invest. 1998; 101:1500-1508). Cross-reactive responses to HSV-1and HSV-2 were present, as were antigen-specific responses to HSVglycoproteins. Normal skin responses were low, and PBMC responses weredeveloping by day 15.

Example 4 Identification of an ICP0 Antigen Recognized by HSV-specificCD8 CTL

This example demonstrates, via expression cloning, the antigenicity ofICP0. In particular, an epitope within amino acids 92-101 of ICP0 isidentified. In addition, the antigenicity of ICP0 is confirmed usingvaccinia. The amino acid numbering uses the nomenclature and numberingof Dolan et al., J. Virol 1998, 72:2010-21.

Materials & Methods

The Cos-7 expression cloning method of Boon et al. was used forexpression cloning (De Plaen E et al. In: Lefkowits I., ed. ImmunologyMethods Manual, v. 2. New York: Academic Press, 1997, 691-718).Interferon-gamma secretion was tested as a CD8 T-cell readout by plating1×10⁴ washed autologous LCL stimulators (mock- or HSV-2 infected at MOI10 for 18 hours) and 5×10⁴ responder TCC in triplicate for 24 hours in200 μl TCM (Tigges M A et al., J. Virol. 1992, 66:1622-34).

Libraries used pcDNA3.1 (+)his A, B, and C (Invitrogen) as expressionvectors. These specific vectors have an intrinsic ATG start 5′ to themultiple cloning site (MCS), yielding fusion proteins of a leaderpeptide and a viral polypeptide fragment. There is a ⅙ chance any viralDNA fragment will be forward and “in-frame” with the ATG. Therefore,three vectors (A, B, and C) are used with an extra 0, 1, or 2 bp betweenATG and the MCS.

Libraries were made from HSV-2 strain HG52 DNA purified (MacLean A R.In: Brown S M, MacLean A R, eds. Methods in Molecular Medicine: HerpesSimplex Virus Protocols, v. 10. Totowa, N J: Humana Press Inc., 1998,19-25) from Vero cells. The ˜155,000 bp genome was digested with Sau3AI, predicted to give 456 fragments averaging several hundred bp long.Ends were partially filled-in and fragments ligated to Xba I-digested,partially filled-in, dephosphorylated A, B, and C vectors in separatereactions for primary libraries. Partial fill-in prevents ligation of >1insert/vector. Contamination with cell DNA was not detected in 20 randomclones. Primary libraries were amplified immediately and saved asaliquots. The goal of six-fold genomic oversampling was met, assumingeach library was only ⅙ forward and in-frame: each primary libraryhad >15,000 transformants. Three thousand clones per library werestudied. Libraries were titered and diluted to 15 clones/well in deepmicrotiter plates. DNA was purified (Millipore 96-well format; silicachemistry) after 18 hr rotation at 300 rpm, 37° C. Yields averaging 10μg/well (spectrophotometer) were obtained, enough for many futurescreens.

Lesion clone RW51 (Table 1) was chosen for expression cloning. The HLArestricting allele of CD8 TCC RW51 is B45 as LCL matched only at B45were lysed in CTL assays. HLA B*4501 cDNA was cloned by RT-PCR. cDNAsynthesis used total RNA from RW LCL (Chomczynski P, Sacchi N. In:Coligan J E et al., eds. Current Protocols in Immunology. New York: JohnWiley and Sons, 1992, 10.11.7-10.11.14), oligo-dT primer and MMLV RT(Pharmacia) with standard protocols (Sambrook J et al., MolecularCloning: a laboratory manual, v. 2, New York: Cold Spring Harbor Press,1989). HLA B*4501 PCR product (primers AAGGTACCATGCGGGTCACGG CACCCCGAAand GGTCTAGAAGTTCGACACTCTCTGTGTAGT; Kpn I and Xba I sites marked; SEQ IDNO: 4 and 5, respectively) was digested, cloned into pcDNA 3.0, andsequenced. It was identical to Genbank 61710 for B*4501. Expression waschecked with FITC-labeled, allele-specific tnAb B12 (One Lambda, Inc.).At 48 hours, 40% of transfected (Fugene 6, Boehringer Mannheim) Cos-7expressed surface HLA B45 by flow cytometry compared to <1% for vector.HLA A*0201, the restricting allele for CD8 TCC RW3 and dkRW22 (Table 3),was similarly cloned and expression documented with mAb MA2.1 (McMichaelA J et al., Human Immunol. 1980, 1:121-29).

To screen libraries for the antigenic protein, Cos-7 cells plated(7,000/well) in flat microtiter plates were co-transfected after 24hours with library pool and B*4501 DNA (50 and 25 ng/well). Cloned RW51T-cells (5×10⁴/well) were added 48 hours later. Supernatant (24additional hours) interferon-gamma ELISA (lower limit of detection, ˜2pg/ml) was done with matched mAb pair (Endogen). Two to four positivepools were found in each reading frame library (A, B, and C). Bacteriafrom positive pools were plated, colonies picked, and DNA made for thenext round of assay. All positive clones had identical 1164 bp HSV-2Sau3A I inserts (FIG. 3) containing exon 1, intron 1, and some of exon 2of the HSV-2 ORF encoding IE protein ICP0. Another 445 bp of genomic DNA5′ to the ATG start of ICP0 was present. Representative positive cloneA1:H3:B8 was selected for further study.

The positive genomic clones in both A and B reading register libraries,and the presence of three stop codons in-frame with the vector ATG andpreceding the ICP0 ATG in both the A and B library positive clones,argues for use of the HSV-2 promoter rather than the vectors' CMVpromoter. Constitutive promoter activity by 5′ elements in the absenceof VP16 (αTIF) and the “viral context” can occur for HSV-1 ICP0.

To find the epitope, an examination was made as to whether and how HSV-1ICP0 mRNA was spliced in the Cos-7 cells. ICP0 mRNA is one of a fewspliced HSV genes; alternative splicing has been reported. Total RNAfrom Cos-7 cells transfected with the (+) genomic fragment A1:H3:B8(Table 4) and MMLV RT were used to make cDNA with primer C (FIG. 3).Primers A at the translational start and primer C were then used in PCR.The sequences of eight cDNA clones all showed splicing. The acceptorsite was 3 bp 3′ to the published site, removing amino acid Q26. Tonarrow down the epitope, A-C (exon1, start of exon 2) and A-B (exon 1)PCR products were cloned into the proper pcDNA3.1-based vector forin-frame expression. The exon-1-exon 2 clone was positive but the exon 1clone was negative (Table 4) when tested for reactivity with T-cellclone RW51.

A vaccinia-ICP0 (Manickan, E et al., J. Virol. 1995, 69(8):4711-4716)was used to confirm the expression cloning identification of ICP0 (FIG.4).

Results

All HSV-specific CD8 clones released IFN-γ in a specific manner (Table3). In addition, the utility of the interferon-gamma assay was examinedas a confirmatory test for HLA restriction. Clone RW51 specificallyreleased interferon-gamma after exposure to Cos-7 cells transfected withHLA B*4501, but not with A*0201, and infection with HSV-2 (Table 3).

TABLE 3 Interferon-gamma secretion (pg/ml by ELISA) from lesion-derivedHSV-specific CD8+ TCC (RW51). stimulator responder TCC autologous LCLmock <5 autologous LCL HSV-2 440 Cos-7 A*0201/HSV-2 <5 Cos-7B*4501/HSV-2 600

TABLE 4 Secretion of interferon-gamma of CD8 TCC RW51 in response toCos-7 cells transfected with various DNAs (or peptide loaded at 1 μM)measured by ELISA in pg/ml. Responses of 5 × 10⁴ TCC to 7 × 10³ Cos-7cells checked at 24 hours. HLA class empty pool clone ICP0 ICP0 ICP0 IcDNA vector A1:H3 A1:H3:B8 exon 1 exon 1,2 92-105 empty not not <2 <2 <2<2 vector done done B*4501 <2 420 >600 <2 >600 1,100

To choose peptides efficiently, a HLA B45 binding motif was derived fromB45-restricted peptides, and pool sequence from peptides eluted fromB*4501. The motif is glutamic acid at position 2, hydrophobic atposition 10 (P1 and P9 in “binding” nomenclature (Rammansee H-G, CurrentOpinion in Immunology 1995, 7:85-96)). Peptide ICP0 92-105(AERQGSPTPADAQG; SEQ ID NO: 19) was active in CTL (FIG. 4) andinterferon-gamma (Table 4) assays. Other candidate exon 2 peptides werenot. The high EC₅₀ value (˜1 μM) may be due to the carboxy-terminus tailpredicted to lie outside the pep tide-binding groove and reduce bindingto HLA B*4501. Vaccinia-ICP0 from B. Rouse (Manickan E et al., J. Virol.1995, 69:4711-16) was grown and titered (Koelle D M et al., J. Virol.1994, 68:2803-10). Clone RW51 specifically lysed vac-ICP0 targets (FIG.4). The availability of the vaccinia was fortuitous, and not required toconfirm the result of expression cloning. To narrow down the epitope, apeptide comprising amino acids 92-101 of ICP0 (AERQGSPTPA; SEQ ID NO: 6)was synthesized. The IC₅₀ for this peptide is between 1 and 10 nanomolar(FIG. 5).

To confirm that patients with HSV-2 infection have T-cells reactive withthe newly discovered T-cell antigen circulating in their peripheralblood, peripheral blood mononuclear cells (PBMC) from the patient fromwhom the lesion-derived clone RW51 was recovered were peptidestimulated. PBMC were cultured for three days at 2×10⁶ cells per 1.88cm² well in 2 ml of T-cell medium containing 1.0 μg/ml peptide HSV-2ICP0 92-101. On the fourth day, IL-2 (32 units/ml) was added. On theeighth day, the cells were washed and restimulated in the same size wellwith an additional 2×10⁶ autologous, irradiated (3300 rad gammairradiation) PBMC, 1.0 μg/ml of the same peptide, and IL-2 (32 U/ml).

Responders were cultured for an additional nine days in the presence ofIL-2 and expanded as necessary. Cytotoxicity assay was performed usingautologous or HLA class I-mismatched LCL treated either with nothing,peptide HSV-2 ICP0 92-101 at 1 μg/ml for 18 hours, or infection withHSV-2 strain 333 at MOI 10 for 18 hours. The cytotoxicity assay was astandard four-hour ⁵¹Cr release assay.

The results (FIG. 6) show that stimulation of PBMC with peptide HSV-2ICP0 92-101 was able to stimulate cells with cytotoxicity towards HSV-2infected cells, and that this activity was not present against HLA classI-mismatched cells. For comparison, the index T-cell clone RW51 was alsoused as an effector cell in this assay and displayed comparable,although slightly higher, cytotoxicity at the effector to target ratioof 10:1 shown in FIG. 6.

Example 5 Identification of an U_(L)47 Antigen Recognized byHSV-specific CD8 CTL

This example demonstrates, via expression cloning, the antigenicity ofan HSV polypeptide encoded by DNA contained within the coding region forprotein U_(L)47. Expression cloning and library preparation were asdescribed in Example 4.

Lesion clone dkRW22.1991 was chosen for expression cloning. This clonehas cytolytic activity against HSV-2 infected, autologous LCL (Table 1).The HLA restricting allele of CD8 TCC dkRW22.1991 is HLA A*0201, asCos-7 cells transfected with HLA A*0201, but not B*4501, and theninfected with HSV-2, specifically stimulated interferon-gamma releasefrom dkRW22.1991 (Table 5). Clone dkRW22.1991 has the followingphenotype by flow cytometry: CD3(+), CD4(−), CD8(+), CD16 and 56(−), andT-cell receptor α/β(+).

Results

To screen libraries for the antigenic protein, Cos-7 cells plated(9,000/well) in flat microtiter plates were co-transfected after 24hours with library pools and A*0201 DNA (50 and 25 ng/well). ClonedT-cells were added 48 hours later, and interferon-gamma assay performedon 24 hour supernatants as described for Example 4. One positive pool inthe library from pCNA3.1-his C was found. Bacteria from this pool wereplated and DNA made from 96 colonies for the next round of assay. Onepositive clone, designated C1F1C7, was found in a follow-up round ofinterferon-gamma release assays. Sequencing of the viral insert revealedthat it was a 1.4 kb Sau3a I fragment of the HSV-2 genome fromnucleotides 102875 to 101383. The sequences encode the C-terminal regionof HSV-2 U_(L)47 from amino acids 292 to 696, a short interveningregion, and then the N-terminal 70 amino acids of HSV-2 U_(L)46.

To partially narrow down the region of HSV-2 DNA encoding the antigenicepitope, the full length genes for U_(L)47 and U_(L)46 of HSV-2 werecloned by PCR using a thermostable DNA polymerase with proofreadingfunction (pfu, Invitrogen). The primers were CTAGGATCCCCTCCGGCCACCATGTCC(5′ primer; SEQ ID NO: 7) and CGATCTAGACCTATGGGCGTGGCGGGC (3′ primer;SEQ ID NO: 8) for U_(L)47, and CGAGGATCCGTCTCCGCCATGCAACGCCG (5′ primer;SEQ ID NO: 9) and CGCTCTAGATTTTAATGGCTCTGGTGTCG (3′ primer; SEQ ID NO:10) for U_(L)46. In each case, the 5′ primer contained an incorporatedBamH I site (underlined) and the 3′ primer contained an incorporated XbaI site (underlined) to facilitate cloning.

The PCR products were digested with BamH I and Xba I and cloned intopcDNA3.1-his-C to yield in both cases in-frame fusion proteins. Thesequences in the fusion regions at the 5′ ends of the HSV-2 genes intopcDNA3.1-his-C were confirmed by sequencing. In addition, all of theU_(L)46 coding sequences contained within the original positive cloneC1F1C7 were deleted by restriction digestion and re-ligation. Thedaughter construct is designated C1F1C7-Apa I(−).

To test the reactivity of lesion-derived T-cell clone, Cos-7 cells weretransfected with A*0201 DNA and either infected with HSV-2 ortransfected with each of these constructs. The results are consistentwith recognition of an antigen encoded by the DNA encoding U_(L)47 ofHSV-2. The clone C1F1C7-Apa I(−) was positive. Because this clone isdeleted of all U_(L)46 sequences, U_(L)46 is not being recognized. Inaddition, the transfection of full-length U_(L)47, but not U_(L)46,together with HLA A*0201 into Cos-7 cells yielded cells thatspecifically stimulated interferon-gamma secretion by clone dkRW22.1991.

TABLE 5 Secretion of interferon-gamma by TCC dkRW22.1991 in response toCos-7 cells transfected with functional HLA class I heavy chain cDNAsand infected with HSV-2 at multiplicity of infection of approximately 5.HLA cDNA none A*0201 A*0201 B*4501 live HSV-2 none none HSV-2 HSV-2IFN-γ, pg/ml <10 <10 >600 <10

TABLE 6 Secretion of interferon-gamma by clone dkRW22.1991 in responseto Cos-7 cells transfected with HLA A*0201 and either infected withHSV-2 as a positive control or co-transfected with eukaryotic expressionvectors containing specific segments of the HSV-2 genome. HLA cDNA NoneA*0201 A*0201 A*0201 A*0201 A*0201 Live HSV-2 None None None None NoneNone HSV-2 DNA None None C1F1C7 C1F1C7 U_(L)47 U_(L)46 Apa I (−) IFN-γ,pg/ml <10 <10 >600 >600 >600 <10

Example 6 Identification of Amino Acids 289-298, 551-559 and 551-561 ofU_(L)47 as Antigens Recognized by HSV-specific CD8 CTL

Materials & Methods

Cell Lines and Viruses: EBV-LCL were made from PBMC in-house; ARENT,PITOUT, HERLUF, and KAS011 were obtained from G. Nepom. HSV-1 E115 andHSV-2 333 and HG52 and recombinant vac-ICP0-HSV-2 (provided by B. Rouse)and wild type vaccinia NY were raised and tittered in Vero or BSC-40cells.

HSV-specific T-cells were obtained from HSV-2 culture-positive buttocklesions. Biopsies were taken on lesion day 5 or from herpetic vesiclefluid. Lymphocytes were expanded in bulk with PHA and IL-2. CD8 cellswere selected with immunomagnetic beads (Minimacs, Miltenyi) and cloned.For subject HV, biopsy tissue was digested for five hours at 37° C. inCollagenase IV-S (Sigma) and the resultant cell suspension cloned inserial 10-fold dilutions. Clones were expanded with anti-CD3 mAb, IL-2,and feeders. Peptide-restimulated PBMC-derived lymphocytes were made byincubating 4×10⁶ PBMC with 1 μg/ml peptide. After three days, 10 U/mlhuman recombinant IL-2 (Chiron) was added. After seven days, responderswere washed and re-plated with 2×10⁶ freshly thawed, irradiatedautologous PBMC, peptide, and IL-2. Cells were assayed on day 14-21.

Expression Cloning: HSV-2 genomic DNA was digested with Sau3A I,re-extracted, and partially filled in with Klenow fragment, dTTP anddCTP. Plasmids pcDNA3.1 (+) myc-his A, B, and C (Invitrogen) weredigested with Xho I and partially filled in with dATP and dGTP. Afterligation, DNA was electroporated into E. coli strain DH10B. Each libraryhad several thousand primary transformants. The majority of each librarywas immediately amplified in bulk (4 ml LB-amp, overnight) andaliquoted. 20 random clones each contained single HSV-2 Sau3A Ifragments. To make DNA for transfection, deep 96-well plates wereinoculated either with libraries at ˜15 colonies/well, or with selectedindividual clones. After overnight growth, DNA was prepared with 96-wellfilters.

To make HLA A*0201, B*4402, B*4403, and B*4501 cDNA, total RNA wasextracted from LCL. cDNA was prepared with oligo-dT and MMLV reversetranscriptase. PCR used pfu DNA polymerase, 2.5 mM (each) dNTP, cDNA,and primers designed to complement the heavy chain gene and containingdistal Kpn I or Xba I sites. Amplimers were digested Kpn I and Xba I andligated into pcDNA3.0. Insert sequences were identical to Genbank.

To study the cDNA species derived from the positive genomic clonecontaining portions of ICP0 (below), Cos-7 cells were transfected withthe ICP0 genomic clone, and total RNA prepared after 48 hours. Theprimer used for cDNA synthesis (TGCTCTAGAGACTCGATCCCTGCGCGTCGG, Xba Isite underlined; SEQ ID NO: 11) was derived from the sequence of the 3′end of the HSV-2 DNA in the ICP0 genomic clone. MMLV reversetranscriptase was used. To examine splicing, PCR used pfu polymerase,cDNA, the above 3′ primer, and 5′ primer TAAGGTACCTGAACCCCGGCCCGGCACGAGC(Kpn I site; SEQ ID NO: 12). To isolate exon 1 of ICP0, PCR used thesame 5′ primer and 3′ primer TGCTCTAGACCAGGCGTGCGGGGCGGCGGG (Xba I site;SEQ ID NO: 13). Product was cloned into pCDNA3.1-his-B.

Full-length U_(L)47 of HSV-2 was PCR-cloned into pCDNA3.1-his-C usingthe same primer identified above (SEQ ID NO: 7, 8). Full-length U_(L)46of HSV-2 was PCR-cloned into pcDNA3.1-his- C with the correspondingprimers identified above (SEQ ID NO: 9, 10). Similarly, constructsexpressing amino acids 1-595 and 1-640 of U_(L)47 were made by PCR,using the above 5′ primer, appropriate 3′ primers, and pCDNA3.1-his-C.Constructs U_(L)47 1-535 and 536-696 were made using a natural Not Isite at aa 535. In-frame fusion was confirmed by sequencing.

Lymphocyte Functional Assays: CTL assays were done by standard 4-hour⁵¹Cr release. Target EBV-LCL were infected 18 hours with HSV at MOI 10;effector:target ration was 20:1. Anti-class I mAb W6/32 was used at 10μg/ml. Actinomycin D was used a 5 μg/ml for 30 min. pre-infection,during 90 minute infection, wash, and assay periods to study the effectof inhibition of viral RNA expression.

IFN-gamma secretion by HSV-reactive CD8 CTL was used as the endpoint toconfirm isolation of functional HLA cDNA and for expression cloning.Cos-7 cells seeded on day one at 9,000 cells/well in 96-well flat-bottomplates were transfected on day two with 50 ng HLA cDNA (Fugene-6). Onday three, cells were infected with HSV-2 333. On day four, 0.7-1.0×10⁵cloned CD8 T-cells were added. Supernatants were saved on day five.

To screen libraries, Cos-7 were co-transfected with 50 ng HLA cDNA and100 ng of library DNA (pools of 15, or single colony). Two days later,1×10⁵ cloned T-cells/well were added and supernatants saved after 24hours. Positive pools were broken down to identify active bacterialclones. The HSV-2 DNA in active clones was sequenced.

Flow Cytometry: Lymphocytes were stained with labeled mAb to CD3, CD4,CD8, CD16/56, TCR αβ, or TCR γδ by standard methods. To measure HLAexpression in transfected Cos-7 cells, trypsinized cells were mixed with1 μg FITC-labeled mAb B12 reactive with HLA B*4501 (One Lambda, Inc. orsupernatant of mAb MA2.1 cells reactive with HLA A*0201, followed byFITC-labeled goat anti-mouse IgG.

HLA Typing: For definition of HLA B44 alleles, direct sequencing ofvariable exons was performed.

ELISA: Gamma-interferon was measured by ELISA with reagents fromEndogen. Plates were coated with 100 μl of 0.25 μg/ml capture mAbM700A-E and blocked with 1% BSA in 0.2 M NaCl, 3 mM KCl, 0.05 M Tris, pH9 (TBS) for one hour. Subsequent incubations were each 100 μl, precededby 3-5 washes with PBS/0.2% Tween-20, and performed with rotation atroom temperature. Samples and standards diluted in TBS with 0.1% BSA,0.05% Tween-20, and 4 μg/ml Immunoglobulin Inhibiting Reagent #6LD1068(Bioreclamation, Inc., East Meadow, N.Y.) (sample buffer) were added for2 hours. Biotinylated detection mAb (M701B) diluted to 100 ng/ml insample buffer was added for one hour. AvidinD:HRP (A-2004) diluted to100 ng/ml in TBS with 1% BSA, 0.05% Tween-20 was added for one hour. TMBsubstrate was added for 10 minutes. Lower limit of detection ranged from2 to 10 pg/ml.

Results are shown in FIGS. 7-10 and in Tables 7-9.

TABLE 7 autologous HLA partially HLA HSV-2/ mismatched¹ matched² T-cellclone mock HSV-1 HSV-2 Act D³ mock HSV-2 allele mock HSV-2 dkRW.1997.511 3.7 73.6 45.1 2.9 4.5 B*4501 0 61.8 dkRW.1991.22 1.2 0.1 38.3 12.1 0 0A*0201 3.3 65.2 HV.1999.23 6 0 56.6 35.8 2.5 2.1 A*0201 0 33.4

TABLE 8 HSV-2 sequence HLA genomic (nucle- HSV-2 ORF(s) T-cell clonecDNA clone otides) amino acids dkRW.1997.51 B*4501 A1:H3:B8  1,858- ICP01-105  3,022 (SEQ ID NO:22) dkRW.1991.22 A*0201 C1:F1:C7 102,875- UL47299-696 . . . 101,383 UL46 1-71 HV.1999.23 A*0201 C2:C10:B9 102,943-UL47 278-298 102,875

TABLE 9 HLA class I alleles Lysis EBV-LCL HLA A HLA B uninfectedHSV-2-infected autologous *01, *0201 *08, *57 9.1 70.4 CW 7477 *0301,*11 *4402, 1801 70.3 94.2 HERLUFF *02 *4402, 35 60.0 nd² HH 7894 *03,*31 *4402, *1524 77.2 75.5 KK 6806 *02, *03 *4402, *2705 57.4 62.3PITOUT *2902 *4403 71.0 51.2 MK 8080 *03, *30 *4405, *39 2.6  1.0

The results show that lesion-infiltrating CD8 CTL recognize immediateearly (ICP0) or virion input (U_(L)47) proteins as predicted by ACT Dinhibition and HSV-encoded TAP and transcriptional inhibitors. Moreover,HSV-2 U_(L)47 289-298/A*0201-specific CD8 CTL cross-react with HLAB*4402 and B*4403, but not B*4405. The TCR may recognize these B44alleles plus a “housekeeping” peptide, currently unknown, present withinB cells and also human and primate renal epithelial cells. The datasuggest that cross reactive T-cells could mediate GVHD when stem cellsfrom a A*0201/not B*4402 or *4403 person are placed into a A*0201, HSV-2infected person as well as graft rejection when a B*4402 or*4403-bearing organ is placed into a A*0201, HSV-2 infected person.

Example 7 Identification of Amino Acids 548-557 of U_(L)47 as AntigensRecognized by HSV-specific CD8 CTL

CD8+ T cell clone cpRW22 (separately derived from same source as dkRW22)was tested against a series of synthetic peptides predicted to bind toHLA-A2 and derived from the HSV-2 gene U_(L)47. One of these peptideswas positively recognized by cpRW22 in an IFNγ ELISPOT assay. Thesequence of the U_(L)47 peptide that scored positive was:NH2-RLLGLADTVV-COOH (SEQ ID NO: 18), which peptide contains amino acids548-557 of U_(L)47.

A series of 10-mer (U_(L)47/549-558, 550-559, 551-560 and 552-561) and9-mer peptides (U_(L)47/548-556, 549-557, 550-558, 551-559 and 552-560)that overlapped U_(L)47/548-557 was prepared to better define theoptimal target peptide. One 9-mer (U_(L)47/551-559) and two 10-mers(U_(L)47/550-559, 551-560) scored strongly positive at lowconcentrations in an ELISPOT assay (FIGS. 11A & 11B). TheU_(L)47/550-559 and U_(L)47/551-559 peptides had similar activities atall peptide concentrations tested.

Example 8 Identification of Amino Acids 550-559 of U_(L)47 as aNaturally Processed Antigen

To determine the naturally processed U_(L)47 peptide, A2-molecules werepurified from 1.5×10¹⁰ C1R-A2/3D9.6H7 cells and the bound peptidesstripped by acid elution. These peptides were fractionated on an HPLCcolumn under the following conditions: TFA ion-pairing agent; 0-10%acetonitrile (ACN) over 5 mins, 10-45% ACN over 50 mins, 45-60% ACN over5 mins. These fractions were tested for the ability to sensitize T2targets for recognition by cpRW22 T cells in an IFN-gamma ELISPOT assay.Targets were T2 cells (20,000) pulsed with 5% of each fraction inserum-free medium +3 μg/ml HuB2M at 32° C. for 4 hours. The targets werethen washed twice and transferred to duplicate wells (10,000/well) ofELISPOT plates. Responders were CTL clone cpRW22 (20,000/well).

Fractions 17, 18 and 23 were found to contain this activity (FIG. 12).Fractions 17 and 18 were subfractionated on the HPLC column under thefollowing conditions: HFBA ion-pairing agent; 0-10% ACN over 5 mins,10-35% ACN over 50 min, 35-60% ACN over 5 mins. Subfractions 24 and 25were found to sensitize T2 cells for recognition by cpRW22 (FIG. 13B;compare FIGS. 13A & 13C). Fraction 23 was subfractionated by HPLC in thesame manner. Subfraction 37 was found to sensitize T2 cells forrecognition by cpRW22 in an IFN-gamma ELISPOT assay (FIG. 14). TheU_(L)47/551-559, 550-559, and 551-560 peptides were run on the HPLCunder the subfractionation conditions and found to elute in fractions 37(U_(L)47/550-559; FIG. 15A), 40/41 (U_(L)47/551-560; FIG. 15B), and 32(U_(L)47/551-559; FIG. 15C).

The U_(L)47/550-559 elutes in the same fraction (37) as does thenaturally processed peptide from C1R-A2/3D9.6H7 cells, and is thereforelikely to have the same sequence as the naturally processed peptide. TheMS/MS data for Fraction 23/Subfraction 37 shows the presence of apeptide with a molecular mass of 961 (FIG. 16). The molecular mass ofU_(L)47/550-559 is also 961. This provides supportive evidence thatU_(L)47/550-559 is the naturally processed U_(L)47 peptide.

The amino acid sequence of the U_(L)47/550-559 peptide is LGLADTVVAC(SEQ ID NO: 1). It was subsequently verified that a gene fragment ofHSV-2 that could encode the U_(L)47/550-559 peptide is contained withinC1R-A2/3D9.6H7 cells. This was done by performing PCR with primers madeto flanking regions of the cloning site of the pBIB retroviral vectorand to the DNA sequence encoding U_(L)47/550-559 (FIG. 17). Using thesePCR primers and varying the PCR conditions, it was demonstrated that theC1R-A2/3D9.6H7 cells contain at least two retroviral inserts derivedfrom HSV-2 (FIGS. 18A-C). One insert encodes two fragments of theU_(L)52 gene. The second insert encodes a large portion of the U_(L)47gene, including the portion encoding the U_(L)47/550-559 peptide.

Example 9 Methods for Identifying Proteins Recognized by HSV-specificCD8 CTL

This example demonstrates how one can identify additional proteinsrecognized by HSV-specific CD8 CTL using lesion-derived material.

Isolation of HS V-Specific CD8 T-Cells from Genital/Buttock HSV-2Lesions

Punch biopsies (3-4 mm) are taken from perirectal, buttock and/or thighskin after cleansing and anesthesia. Lesions from suspected primaryherpes are biopsied as soon as possible, and serial biopsies at leasttwice during primary infection are preferred. Recurrent genital HSV-2lesions in healing stages (late ulcer/crust) are preferred forantigen/epitope discovery as LIL from such lesions have high CTLactivity. Portions of lesions can be snap frozen in isopentane/liquidnitrogen in OCT media for immunohistology. A portion of the biopsy isdissociated and cells grown in limiting dilution, and a portion used forbulk culture (Koelle D M et al., J. Clin. Invest. 1998, 101:1500-1508).LIL are expanded in bulk by mincing tissue and stimulating with 0.8μg/ml PHA and 7.5×10⁵ feeders PBMC/well in 48-well plates in T-cellmedium with acyclovir (50 μM). Expansion is assisted by IL-2 (50 U/ml,Hemagen) and usually yields 1-5×10⁷ cells in 14-21 days. CTL activity ofCD8-selected cells is tested against autologous and allogeneic mock- andHSV-2 infected LCL in 4-hour ⁵¹Cr release assays at effector:target 20:1(Tigges M A et al., J. Virol. 1992, 66:1622-34). Lytic activity at thisstage is predictive of recovery of HSV-specific CD8 CTL clones.

To increase the recovery of rare CD8 CTL or CTL that might have a growthdisadvantage in bulk culture, one can bypass the initial bulk expansionstep. HSV-2 lesions are vesicular during the mid-phase of lesionevolution. HSV-specific CD8 CTL can be cloned from vesicle fluid asfollows. Vesicles are broken and fluid recovered with cell scrapers intomedium. A portion is used for cytospin preps (preserved at −70° C. afterfixation). After Ficoll underlay and standard density gradientcentrifugation, cells at the interface are washed and plated in serialdilutions from 100 to 1 cell/well in 96-well U bottom plates togetherwith cloning cocktail (below). The cell recovery from vesicles istypically about 1×10^(4-2×10) ⁵ per lesion.

T-cell cloning uses established procedures (Koelle D M et al., J.Infect. Dis. 1994, 169:956-61). CD8-selected cells from a round of bulkexpansion of LIL are seeded at 2 and 0.3 cells/well. Cells from freshlydisrupted lesion biopsies or vesicle fluid are plated in a modifiedlimiting dilution scheme starting at 30-100 cells/well and decreasing at2-3 fold steps down to 1 cell/well as reported in Koelle et al., 1994,supra. For CD8-enriched fresh LIL and vesicle cells, a portion can beexpanded in bulk (Koelle D M et al., J. Clin. Invest. 1998,101:1500-1508). Microcultures are fed twice weekly with IL-2 andscreened at ˜14 days. The percent of wells showing growth at each inputnumber is recorded to estimate the probability of clonality ofmicrocultures.

Screening Candidate Cultures

A preferred screen for candidate cultures is a split-well CTL assayagainst autologous LCL infected (18 hours, MOI 10) by HSV-2 oruninfected. LCL are EBV-transformed B-cell lines (Koelle D M et al., J.Clin. Invest. 1993, 91:961-68; Miller G et al., Proc. Natl. Acad. Sci.USA 1972, 69:383-87) that take about six weeks to establish from PBMC.LCL are permissive for HSV infection, but are relatively resistant toHSV-mediated HLA class I downregulation in comparison to dermalfibroblasts. Most subjects are enrolled and LCL made prior to biopsy.LCL will therefore be available when TCC are ready for screening.Preferably, the autologous HSV-2 are isolated, grown and titered on Verocells (Koelle et al., 1993, supra).

For clones derived from bulk-expanded LIL, the cell input numberyielding 37% or less of wells positive for growth are designated asprobable “clones”. Half of each microculture is plated in duplicate(final, ⅛ of the culture/assay well) with 2×10³ targets for aneffector:target ratio of ˜15:1. Clones with a net lysis ofHSV-2-infected targets of 15% above their lysis of uninfected targetsare considered positive. Clones with CTL activity are analyzed by flowcytometry, and CD8-bearing CTL clones are expanded. Microcultures fromfresh, disrupted lesion biopsies and vesicles will have been expanded ina limiting dilution format (above). Without the prior round of bulkexpansion, there will be less of a chance that microcultures willcontain “sister” clones, although it is possible that identical cellsmay be independently recovered from the fresh lesion material inseparate microcultures.

Expanding Cultures with CTL Activity

T-cells scoring positive in screening assays are expanded by the methodof Riddell et al. (Nature Medicine 1996, 2:216-23; U.S. Pat. No.5,827,642). The “leftover” half of cells in an original microculturewell (˜5×10⁴ cells) is mixed in 25 ml T-cell medium (Koelle D M et al.,J. Infect. Dis. 1994, 169:956-61) with 2.5×10⁷ irradiated (3300 rad)mixed allogeneic PBMC, 5×10⁶ irradiated (8000 rad) LCL, and 30 ng/ml mAbOKT3 (anti-CD3). At 24 hours and then twice weekly, rhIL-2 (50 U/ml,Chiron, Emeryville, Calif.) is added. OKT3 is removed by washing on dayfour. Typically, the T-cells expand to ˜1-5×10⁷ cells at the end of thefirst cycle. A confirmatory CTL assay can be done when growth visiblyslows at about 12 days. The cell number stored after an identical-secondcycle is essentially unlimited, as a further 200-1000 fold expansionusually occurs. Thawed aliquots of expanded cells work in CTL,proliferation, and cytokine assays. About 10-20% of clones fail toexpand; loss of antigenic specificity is rare, but loss of replicativepotential may occur.

The Cos-7 co-transfection method described above can be used forexpression cloning. DNA from the sequenced HSV-2 strain HG52 can beused, digested with Sau3A I and ligated into each member of the pcDNA3.1(+) his series. The cDNA encoding the HLA class I heavy chainsrestricting the TCCs selected for expression cloning can be cloned, ifnecessary, by RT-PCR into pcDNA3.0 as described above. A universalmethod has been published (Ennis P D et al., Proc. Natl. Acad. Sci. USA1990, 87:2833-37). Proof-reading polymerase can be used and cDNAssequenced. Primers are allele-specific perfect matches with “tails”containing endonuclease sites not present in the target sequence.Undesired heavy chain PCR product (which may be co-amplified) can bereduced by digestion of PCR product with an enzyme that preferentiallycuts the undesired cDNA. To test cDNA function, it can be 1) checked forcell surface expression in 48 hour-transfected Cos-7 cells withallele-specific mAb, and 2) checked for presentation of HSV-2 antigenpresentation by the method illustrated in Table 3 above. The expectedresults are specific staining of Cos-7 cells with allele-specific mAbafter transfection of heavy chain; empty vector and control mAb areincluded. Specific stimulation of CD8 TCC interferon-gamma secretion byCos-7 cells transfected with the heavy chain and infected with HSV-2 isexpected.

The number of clones screened per library will depend on the number ofrestriction fragments generated in making the library, but willtypically be several thousand. Pool size (number of clones transfectedper well of Cos-7 cells) will start at ˜15 viral DNA fragments/well.Positive pools are broken down and individual clones tested. Positiveclones are sequenced and compared to the published HSV-2 sequence toidentify antigens.

Epitope Mapping

Epitope mapping can be done with molecular, bioinformatic, and syntheticmethods. Genomic library screening (above) yields gene fragments asinitial “positives” that range from 25 to 300 amino acids long. TheHSV-2 coding sequences in positive molecular clones can be shortenedusing standard methods, such as exonuclease III digestion (Gavin M A etal., J. Immunol. 1993, 151:3971-80) to make nested truncations of theHSV-2 insert or cleavage of HSV-2 DNA at internal restriction sites andreconstruction of plasmids. It is preferable to use PCR with aproof-reading polymerase to re-amplify a portion of the positiveconstruct. Truncations are designed for a 50-100 amino acid-longpositive fragment. For motif-matching peptides, the P1 “anchor” isplaced at residue 2 of synthetic peptides, since the N-terminal peptideat position “P minus 1” frequently faces “up” to the TCR and is requiredfor T-cell triggering. If no motif is known, 15-mer peptides overlappingby five are made. Peptides are tested at 1 and 10 μM in CTL and/orinterferon-gamma assays.

If these methods do not find the epitope, further molecular “trimming”from both ends of the active HSV-2 construct can be done to find theminimal coding sequence (Schneider J et al., Int. J. Cancer 1998,75:451-58). If this peptide still is not positive in CTL assay, it maybe that post-translational modification is required. The peptidepredicted to be positive by molecular genetic methods is loaded into theAPC by electroporation or osmotic shock (Chen W et al., J. Immunol.Methods 1993, 15:49-57).

Example 10 ICP0 Stimulation of CTL Responses in Additional HLA-B45Subjects

This example demonstrates that other HLA-B45 positive donors havedetectable CD8+ T cell responses to the previously defined ICP0 92-101peptide.

Peptide restimulation in bulk format are appropriate for sensitivedetection of CTL, while lesion derived antigen (LDA) formats yield CTLlevels, but require prolonged cell replication for detection. In thisexample, 4×10⁶ PBMC in 2 ml T-cell medium were stimulated with 1 μg/mlHSV-2 peptides, and IL-2 (10-30 U/ml) was added on day 3. On day 8,responders were washed and restimulated in 2 ml with 2×10⁶ autologousirradiated PBMC, fresh peptide, and IL-2, and split as necessary untilassay on day 14-16. For two HLA B*4501-bearing persons including theindex subject, convincing HLA class-restricted CD8 CTL were detectedthat not only lysed peptide-loaded targets, but also killedHSV-2-infected targets and were inhibited by anti-class I mAb (Table10).

TABLE 10 Lysis of HLA B*4501 LCL by PBMC stimulated with peptide HSV-2ICP0 92-101, or (+) control clone RW.1997.51. Results are percentspecific release in four-hour CTL assays at effector to target ratio of10:1-20:1. target¹ RW RW RW RW HSV-2/ HV HV HV effector mock peptide¹HSV-2 anti-class I² mock peptide HSV-2 RW PBMC 1 45.3 48.2 12.2 0 −1 0PO PBMC 0 54.9 33.5 5.8 4 −1 0 clone 0 65.3 67.3 5.2 1 0 2 RW.1997.51¹Target LCL (RW = B*4501, HV = not B*4501) loaded with 1 μg/ml ICP092-101 for 90 minutes, or HSV-2 infection, MOI 5, 18 hours. ²Anti-HLAclass I mAb W6/32 included at 10 μg/ml.

Example 11 U_(L)47 Stimulation of CTL Responses in Additional HLA-A2Subjects

This example demonstrates that other HLA-A2 positive donors havedetectable CD8+ T cell responses to the previously defined U_(L)47peptide 550-559.

The U_(L)47 gene was amplified by PCR methods from genomic HSV-2 (strain333) DNA and cloned into the pBIB retroviral vector. DNA was preparedfrom several U_(L)47/pBIB clones and transfected into VA13 cells thatstably express HLA-A2. These transfectants were recognized by theU_(L)47/550-559-specific, HLA-A2-restricted CTL clone cpRW22 (FIG. 19).U_(L)47/550-559 peptide-pulsed VA13/A2 cells were used as a positivecontrol.

PBMC from several HLA-A2 positive donors (RW1874, HV5101, AD116, AD120and AD124), some of whom were seropositive for HSV-2, were tested forthe presence of U_(L)47-specific CD8+ T cells. TheU_(L)47/550-559-specific, HLA-A*0201-restricted CTL clone cpRW22 waspreviously derived from donor RW1874. The HSV-2U_(L)47/289-298(FLVDAIVRVA; SEQ ID NO: 20)-specific, A2-restricted cloneHV2 was derived from donor HV5101. Thus, detection of U_(L)47-specificCD8+ T cells in the PBMC of RW1874 and HV5101 was expected. PBMC werestimulated twice in vitro with 1 μg/ml of one of three A2-restrictedepitopes: influenza M1/58-66, U_(L)47/289-298 or U_(L)47/550-559. The Tcells were then tested in a ⁵¹Cr-release assay against targets pulsedwith either no peptide, the stimulating peptide, or a control peptide(RT) derived from HIV. All of the donors tested are known to be HIVnegative.

Results are shown in FIGS. 20A-L. RW1874 responded only to the M1 andU_(L)47/550-559 peptides (FIGS. 20A-C). HV5101 responded to all threepeptides (FIGS. 20D-F), even though U_(L)47/289-298 is the only HSV-2peptide that was identified using cells from this donor. AD120 did notrespond to any of the three peptides (FIGS. 20G-I), suggesting that itmay belong to a significantly distinct A2 subtype. AD124 responded tothe M1, but not to either of the U_(L)47 peptides (FIGS. 20J-L). Thiswas expected because AD124 is seronegative for HSV. These results aresummarized in Table 11.

TABLE 11 Summary of CD8+ T cell responses to UL47 epitopes. SerostatusHLA- CTL response (PBMC) Donor A2 HSV-1 HSV-2 M1 UL47/550 UL47/289 RTRW1874 + + + + − − HV5101 + + + + + − AD116 + − + + − − − AD120 + + + −− − − AD124 + − − + − − −

Those skilled in the art will appreciate that the conceptions andspecific embodiments disclosed in the foregoing description may bereadily utilized as a basis for modifying or designing other embodimentsfor carrying out the same purposes of the present invention. Thoseskilled in the art will also appreciate that such equivalent embodimentsdo not depart from the spirit and scope of the invention as set forth inthe appended claims.

1. An immunogenic composition comprising a herpes simplex virus (HSV) polypeptide, wherein the HSV polypeptide consists of amino acids 1-105 (SEQ ID NO: 22), 92-101 corresponding to SEQ ID NO: 6 or 92-105 (SEQ ID NO: 19) of ICP0, and a pharmaceutically acceptable carrier.
 2. The immunogenic composition of claim 1, wherein the polypeptide is a fusion protein.
 3. The immunogenic composition of claim 2, wherein the fusion protein is soluble.
 4. The immunogenic composition of claim 1, further comprising an adjuvant.
 5. A method of inducing an immune response against an HSV infection in a subject comprising administering the composition of claim 1 to the subject.
 6. The immunogenic composition of claim 1, wherein the HSV is HSV-2.
 7. An immunogenic composition comprising an isolated HSV polypeptide produced by: (a) culturing a host cell transformed with a vector comprising a polynucleotide that encodes an HSV polypeptide, wherein the HSV polypeptide consists of amino acids 1-105 (SEQ ID NO: 22), 92-101 corresponding to SEQ ID NO: 6 or 92-105 corresponding to SEQ ID NO: 19 of ICP0, and (b) recovering the polypeptide so produced.
 8. The immunogenic composition of claim 7, wherein the polypeptide is a fusion protein.
 9. The immunogenic composition of claim 8, wherein the fusion protein is soluble.
 10. The immunogenic composition of claim 7, further comprising an adjuvant.
 11. A method of inducing an immune response against an HSV infection in a subject comprising administering the composition of claim 7 to the subject.
 12. An immunogenic composition comprising a polynucleotide that encodes an HSV polypeptide, wherein the HSV polypeptide consists of amino acids 1-105 (SEQ ID NO: 22) 92-101 corresponding to SEQ ID NO: 6 or 92-105 corresponding to SEQ ID NO: 19 of ICP0, and a pharmaceutically acceptable carrier.
 13. The immunogenic composition of claim 12, wherein the HSV is HSV-2.
 14. The immunogenic composition of claim 12, wherein the polypeptide is a fusion protein.
 15. The immunogenic composition of claim 14, wherein the fusion protein is soluble.
 16. The immunogenic composition of claim 12, further comprising an adjuvant.
 17. A method of inducing an immune response against an HSV infection in a subject comprising administering the composition of claim 12 to the subject. 